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One of the key intermediates, 5-hydroxyvaleric acid (5-HV), is used in the synthesis of polyhydroxyalkanoate monomer, δ-valerolactone, 1,5-pentanediol (1,5-PDO), and many other substances. Due to global environmental problems, eco-friendly bio-based synthesis of various platform chemicals and key intermediates are socially required, but few previous studies on 5-HV biosynthesis have been conducted. To establish a sustainable bioprocess for 5-HV production, we introduced gabT encoding 4-aminobutyrate aminotransferase and yqhD encoding alcohol dehydrogenase to produce 5-HV from 5-aminovaleric acid (5-AVA), through glutarate semialdehyde in Escherichia coli whole-cell reaction. As, high reducing power is required to produce high concentrations of 5-HV, we newly introduced glucose dehydrogenase (GDH) for NADPH regeneration system from Bacillus subtilis 168. By applying GDH with D-glucose and optimizing the parameters, 5-HV conversion rate from 5-AVA increased from 47% (w/o GDH) to 82% when using 200 mM (23.4 g/L) of 5-AVA. Also, it reached 56% conversion in 2 h, showing 56 mM/h (6.547 g/L/h) productivity from 200 mM 5-AVA, finally reaching 350 mM (41 g/L) and 14.6 mM/h (1.708 g/L/h) productivity at 24 h when 1 M (117.15 g/L) 5-AVA was used. When the whole-cell system with GDH was expanded to produce 1,5-PDO, its production was also increased 5-fold. Considering that 5-HV and 1,5-PDO production depends heavily on the reducing power of the cells, we successfully achieved a significant increase in 5-HV and 1,5-PDO production using GDH., Competing Interests: Declaration of Competing Interest None., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Reaction of 2,2'-bipyridine (2,2'-bipy) or 1,10-phenantroline (phen) with [Mn(Piv) 2 (EtOH)] n led to the formation of binuclear complexes [Mn 2 (Piv) 4 L 2 ] (L = 2,2'-bipy ( 1 ), phen ( 2 ); Piv - is the anion of pivalic acid). Oxidation of 1 or 2 by air oxygen resulted in the formation of tetranuclear Mn II/III complexes [Mn 4 O 2 (Piv) 6 L 2 ] (L = 2,2'-bipy ( 3 ), phen ( 4 )). The hexanuclear complex [Mn 6 (OH) 2 (Piv) 10 (pym) 4 ] ( 5 ) was formed in the reaction of [Mn(Piv) 2 (EtOH)] n with pyrimidine (pym), while oxidation of 5 produced the coordination polymer [Mn 6 O 2 (Piv) 10 (pym) 2 ] n ( 6 ). Use of pyrazine (pz) instead of pyrimidine led to the 2D-coordination polymer [Mn 4 (OH)(Piv) 7 (µ 2 -pz) 2 ] n ( 7 ). Interaction of [Mn(Piv) 2 (EtOH)] n with FeCl 3 resulted in the formation of the hexanuclear complex [Mn II 4 Fe III 2 O 2 (Piv) 10 (MeCN) 2 (HPiv) 2 ] ( 8 ). The reactions of [MnFe 2 O(OAc) 6 (H 2 O) 3 ] with 4,4'-bipyridine (4,4'-bipy) or trans -1,2-(4-pyridyl)ethylene (bpe) led to the formation of 1D-polymers [MnFe 2 O(OAc) 6 L 2 ] n ·2 n DMF, where L = 4,4'-bipy ( 9 ·2DMF), bpe ( 10 ·2DMF) and [MnFe 2 O(OAc) 6 (bpe)(DMF)] n ·3.5 n DMF ( 11 ·3.5DMF). All complexes were characterized by single-crystal X-ray diffraction. Desolvation of 11 ·3.5DMF led to a collapse of the porous crystal lattice that was confirmed by PXRD and N 2 sorption measurements, while alcohol adsorption led to porous structure restoration. Weak antiferromagnetic exchange was found in the case of binuclear Mn II complexes ( J Mn-Mn = -1.03 cm -1 for 1 and 2 ). According to magnetic data analysis ( J Mn-Mn = -(2.69 ÷ 0.42) cm -1 ) and DFT calculations ( J Mn-Mn = -(6.9 ÷ 0.9) cm -1 ) weak antiferromagnetic coupling between Mn II ions also occurred in the tetranuclear {Mn 4 (OH)(Piv) 7 } unit of the 2D polymer 7 . In contrast, strong antiferromagnetic coupling was found in oxo-bridged trinuclear fragment {MnFe 2 O(OAc) 6 } in 11 ·3.5DMF ( J Fe-Fe = -57.8 cm -1 , J Fe-Mn = -20.12 cm -1 ).

Herein, this study extracted nanocrystalline cellulose (NC) and silica (SiO 2 ) from raw oil palm leaves (OPL), and employed as nanofillers in polyethersulfone (PES) to produce NC-SiO 2 -PES as support to immobilize Candida rugosa lipase (CRL) (NC-SiO 2 -PES/CRL). XRD, TGA-DTG and FTIR-ATR data affirmed that NC and SiO 2 were isolated from OPL with corresponding crystallinity indices of 68 % and 70 %. A 0.02 cm membrane size with 5% (w/v) of NC-SiO 2 without PVP K30 was optimal for membrane fabrication. CRL immobilized on the Glut-AP-NC-SiO 2 -PES membrane gave a higher conversion of pentyl valerate (PeVa) (91.3 %, p < 0.05) compared to Glut-NC-SiO 2 -PES (73.9 %) (p < 0.05). Characterization of the NC-SiO 2 -PES/CRL biocatalyst verified the presence of CRL. Hence, raw OPL is a proven good source of NC and SiO 2 , as reinforcement nanofillers in PES. The overall findings envisage the promising use of NC-SiO 2 -PES/CRL to catalyze an expedient and high yield of PeVa, alongside the suitability of NC-SiO 2 -PES for activating other enzymes., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Synthesis of (3-aminopropyl) triethoxysilane (APTES)-functionalized graphene oxide (GO) nanosheets, statistical optimization of conditions for immobilization of Bacillus atrophaeus lipase (BaL) on as-synthesized support, and application of the immobilized BaL for esterification of valeric acid were carried out in this investigation. The optimum specific activity of the immobilized BaL (81.60 ± 0.28 U mg -1 ) was achieved at 3 mg mL -1 of GO-NH 2 , 50 mM of phosphate buffer, pH 7.0, 60 min sonication time, 100 mM glutaraldehyde, 25 U mL -1 of enzyme, and 8 h immobilization time at 4 °C. The immobilized BaL retained about 90% of its initial activity after 10 days of storage. Moreover, about 70% of the initial activity of the immobilized BaL was retained after 10 cycles of application. The results of esterification studies exhibited that maximum pentyl valerate synthesis using the free BaL (34.5%) and the immobilized BaL (92.7%) occurred in the organic solvent medium (xylene) after 48 h of incubation at 60 °C.

Ample evidence suggests that H₂S is an important biological mediator, produced by endogenous enzymes and microbiota. So far, several techniques including colorimetric methods, electrochemical analysis and sulfide precipitation have been developed for H₂S detection. These methods provide sensitive detection, however, they are destructive for tissues and require tedious sequences of preparation steps for the analyzed samples. Here, we report synthesis of a new fluorescent probe for H₂S detection, 4-methyl-2-oxo-2 H -chromen-7-yl 5-azidopentanoate ( 1 ). The design of 1 is based on combination of two strategies for H₂S detection, i.e., reduction of an azido group to an amine in the presence of H₂S and intramolecular lactamization. Finally, we measured salivary H₂S concentration in healthy, 18⁻40-year-old volunteers immediately after obtaining specimens. The newly developed self-immolative coumarin-based fluorescence probe (C 15 H 15 N₃O₄) showed high sensitivity to H₂S detection in both sodium phosphate buffer at physiological pH and in saliva. Salivary H₂S concentration in healthy volunteers was within a range of 1.641⁻7.124 μM.

The chemical-catalyzed transesterification process to produce biofuels i.e. pentyl valerate (PeVa) is environmentally unfriendly, energy-intensive with tedious downstream treatment. The present work reports the use of Rhizomucor miehei lipase (RML) crosslinked onto magnetic chitosan/chitin nanoparticles (RML-CS/CH/MNPs). The approach used to immobilize RML onto the CS/CH/MNPs yielded RML-CS/CH/MNPs with an immobilized protein loading and specific activity of 7.6 mg/g and 5.0 U·g -1 , respectively. This was confirmed by assessing data of field emission scanning electron microscopy, X-ray diffraction, thermal gravimetric analysis and Fourier transform infrared spectroscopy. A three-level-four-factor Box-Behnken design (incubation time, temperature, substrate molar ratio, and enzyme loading) was used to optimize the RML-CS/CH/MNP-catalyzed esterification synthesis of PeVa. Under optimum condition, the maximum yield of PeVa (97.8%) can be achieved in 5 h at 50 °C using molar ratio valeric acid:pentanol (1:2) and an enzyme load of 2 mg/mL. Consequently, operational stability experiments showed that the protocol adopted to prepare the CS/CH/MNP nanoparticles had increased the durability of RML. The RML-CS/CH/MNP could catalyze up to eight successive esterification cycles to produce PeVa. The study also demonstrated the functionality of CS/CH/MNP nanoparticles as an eco-friendly support matrix for improving enzymatic activity and operational stability of RML to produce PeVa., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Three novel N-(α-bromoacyl)-α-amino esters: methyl 2-(2-bromo-3-methylbutanamido)pentanoate (1), methyl 2-(2-bromo-3-methylbutanamido)-2-phenylacetate (2) and methyl 2-(2-bromo-3-methylbutanamido)-3-phenylpropanoate (3) were synthesized. Single crystal X-ray diffraction data are reported for compounds 1 and 2. The cytotoxicity, antiinflammatory and antibacterial activity of compounds 1-3 were investigated. Additionally, the physico-chemical properties of studied compounds were calculated and an in silico toxicological study of compounds 1-3 was performed. The low level of cytotoxicity and absence of antibacterial and anti-inflammatory activity of 1-3 in tested concentrations might be a beneficial prerequisite for their incorporation in prodrugs.

Pentyl valerate was synthesized biocatalytically using Candida rugosa lipase (CRL) immobilized in microemulsion based organogels (MBGs). The optimum conditions were found to be pH 7.0, temperature of 37 °C, ratio of concentration of water to surfactant (Wo) of 60, and the surfactant sodium bis-2-(ethylhexyl)sulfosuccinate (AOT) for MBG preparation. Although kinetic studies revealed that the enzyme in free form had high affinity towards substrates (K(m) = 23.2 mM for pentanol and 76.92 mM for valeric acid) whereas, after immobilization, the K(m) values increased considerably (74.07 mM for pentanol and 83.3 mM for valeric acid) resulting in a slower reaction rate, the maximum conversion was much higher in case of immobilized enzyme (~99%) as compared to free enzyme (~19%). Simultaneous effects of important parameters were studied using response surface methodology (RSM) conjugated with Box-Behnken design (BBD) with five variables (process parameters), namely, enzyme concentration, initial water content (Wo), solvent used for MBG preparation, substrate ratio and time, and response as the final product formation, that is, pentyl valerate (%). The MBGs were reused for 10 consecutive cycles for ester synthesis. Efficacy of AOT/isooctane as dehydrating agent for extracting excess water from MBGs was found to exert a positive effect on the esterification reaction.

Despite the recent research interest in the field of nanoparticles delivery system, their structure modification and transport behavior of various hydrophobic drugs is poorly developed. In this article the synthesis of novel amphiphilic diblock copolymer poly([R]-3-hydroxyvalerate)-block-monomethoxy poly(ethylene glycol) (PHV-block-mPEG) was undertaken by modifying the structure of biodegradable and hydrophobic poly([R]-3-hydroxyvalerate) (PHV) with hydrophilic monomethoxy poly(ethylene glycol) (mPEG). The chemical combination of the two blocks was carried out in the melt using bis(2-ethylhexanoate) tin as transesterification catalyst. The synthesized product was characterized by gel permeation chromatography (GPC), 1H nuclear magnetic resonance (NMR) and differential scanning calorimetry (DSC) analysis. The block copolymer self-assembled into amphiphilic nanoparticles with a core of hydrophobic PHV and a shell of hydrophilic mPEG in aqueous solution. Characterization of the nanoparticles showed the formation of discrete, spherically shaped nanoparticles with mean particle size of 200 +/- 1 nm and zeta potential of -14 +/- 1 mV. A hydrophobic drug thymoquinone was efficiently incorporated into the core hydrophobic domain of the nanoparticles and its release kinetics was studied in vitro. The amphiphilic PEGylated nanoparticles showed biocompatibility when checked in neuronal hippocampal cells of prenatal rat. Our results suggest that the amphiphilic nanoparticles with core-shell structures are potentially useful to develop novel drug carriers.

In our previous study, a surfactant-coated Candida rugosa lipase immobilized in microemulsion-based organogels was exploited for the synthesis of ethyl isovalerate. In the present study, we are focusing on the effective reuse of lipase immobilized in microemulsion-based organogels (MBGs) in terms of retainment of the catalytic activity. As water is one of the co-products in esterification reactions, the removal of water becomes a priority to allow the reaction to work in the forward direction and to prevent back hydrolysis. Taking this fact into consideration, the lipase-containing microemulsion-based organogels were given pretreatment and/or several intermittent treatments with dry reverse micellar solution of AOT in organic solvent during repeated cycles of ester synthesis. The pretreated MBGs with dry reverse micellar solution exhibited lower water content and higher initial rates of esterification in comparison with untreated freshly prepared MBGs. The esterification efficiency of untreated MBGs started decreasing after 5 cycles of reuse and was almost completely lost by the end of the 8th cycle. In contrast, pretreated MBGs exhibited a gradual decrease in esterification efficiency after 5 cycles and retained about 80% of the initial activity at the end of the 8th cycle. The intermittent treatment of MBGs after every 3 cycles resulted in enhanced reusability of immobilized lipase for up to 9 cycles without significant loss in esterification activity, after which it resulted in a slow decrease in activity with about 27% lower activity at the end of the 12th cycle. Furthermore, the treatment conditions such as concentration of AOT in liquid dessicant and time of treatment were optimized with respect to our system. The granulated MBGs proved to be better in terms of initial esterification rates (1.2- fold) as compared with the pelleted MBGs.

A 23-26-carbon chain length range of omega-19 (1'R,2'S) cyclopropane fatty acids, related to mycobacterial mycolic acids, has been prepared. The key cyclopropyl intermediate, (1'R,2'S)-(Z)-1-formyl-2-octadecylcyclopropane, underwent Wittig chemistry with various reagents to provide vinylic precursors, which were selectively reduced to the corresponding saturated omega-19 cyclopropane fatty acids or esters. The 24-carbon omega-19 cyclopropane ester was made by chain elongation of the 23-carbon ester. Saturated and unsaturated chiral cyclopropane acids and esters were assayed, using wall extracts of Mycobacterium smegmatis; the incorporation of 14C-acetate was used to measure inhibition or stimulation of mycolic acid synthesis. Minor inhibition (2-3%) was shown by the 23- and 24-carbon saturated esters; all the other compounds were stimulants. The most effective (38-55%) stimulators of mycolate synthesis were the unsaturated esters with 23- and 26-carbons and the saturated and unsaturated 25-carbon acids.

Immobilized lipase from Rhizomucor miehei (Lipozyme IM-20) was used to catalyze the esterification reaction between isovaleric acid and ethanol to synthesize ethyl isovalerate in n-hexane. Response surface methodology based on five-level four-variable central composite rotatable design was employed to optimize four important reaction variables such as enzyme/substrate E/S ratio, substrate concentration, incubation time, and temperature affecting the synthesis of ethyl isovalerate. The optimum conditions predicted for achieving maximum ester yield (500 mM) are as follows: E/S ratio, 48.41 g/mol; substrate concentration, 1 M; reaction time, 60 h; temperature, 60 degrees C. The predicted value matched well with experimentally obtained value of 487 mM.

Polymerization of beta-butyrolactone (BBL) and beta-valerolactone (BVL) using the zinc alkoxide initiator (BDI-1)ZnO(i)()Pr [(BDI-1) = 2-((2,6-diisopropylphenyl)amido)-4-((2,6-diisopropylphenyl)imino)-2-pentene] proceeds very rapidly under mild conditions to produce poly(3-hydroxybutyrate) (PHB) and poly(3-hydroxyvalerate) (PHV), respectively. For the monomer-to-initiator ratio 200:1, PHB number-average molecular weights (M(n)) are proportional to conversion throughout the reaction and polydispersity indices (PDIs) are narrow, consistent with a living polymerization. Higher monomer-to-initiator ratios can be used to achieve high molecular weight PHB (M(n) > 100 000). End-group analysis verifies that the polymerization of BBL follows a coordination-insertion mechanism, where complexes of the form (BDI-1)ZnOCH(Me)CH(2)CO(2)R are the active species. Variable temperature NMR experiments show that (BDI-1)ZnO(i)()Pr is monomeric in benzene-d(6) solution. In contrast, (BDI-2)ZnO(i)()Pr [(BDI-2) = 2-((2,6-diethylphenyl)amido)-4-((2,6-diethylphenyl)imino)-2-pentene] is a poor initiator at room temperature because it prefers to form a bis-mu-isopropoxide dimer in solution. According to kinetic studies, propagation by (BDI-1)ZnO(i)()Pr is first order in both monomer as well as (BDI-1)ZnO(i)()Pr concentration. These results lead us to propose a monometallic active species. Several results suggest that elimination side reactions are slowly catalyzed by zinc alkoxides, leading to degradation of the polymer.

A new cyclodextrin (CD) derivative, 2,6-di-O-benzyl-3-O-valeryl-beta-CD, was synthesized and characterized by 1H NMR and IR. Using the beta-CD derivative as chiral stationary phase of capillary gas chromatography, one chiral column was prepared. On this column, the enantiomeric excesses (e.e.) of 1-(2,4-dichlorophenyl) ethanol obtained by asymmetric catalytic hydrogenation of 2,4-dichloroacetophone and trans-3-propyloxiranemethanol synthesized by Sharpless epoxidation of trans-2-hexenol were determined and the catalytic reactions were evaluated. The results are satisfactory.

[structure: see text]. Several conformationally rigid analogues of the methylvalerate subunit contained within the linker domain of the antitumor antibiotic bleomycin have been prepared. These compounds have been protected in a fashion suitable for the solid-phase synthesis of bleomycin. Bleomycin congeners containing these analogues should facilitate a more detailed understanding of the nature of the conformational bend that the methylvalerate moiety is thought to impart to the natural product.

3-O-Benzyl-alpha-D-xylopyranose 1,2,4-orthopivalate (1) was newly synthesized and polymerized under cationic polymerization reaction conditions in order to synthesize stereoregular (1-->4)-beta-D-xylopyranan. Although the polymerization of orthopivalate 1 was carried out under various reaction conditions, a non-stereoregular polymer, but mainly consisting of (1-->4)-beta-xylopyranose units, was obtained. Comparing these results with those of glucose 1,2,4-orthopivalates, it was revealed that not only the substituents in the C-2 and C-3 positions, but also the CH(2)OR group in glucose 1,2,4-orthopivalate, largely contribute to (1-->4)-beta-glucosidic bond formation by the ring-opening polymerization.

The design of potent protein kinase C (PK-C) ligands with low nanomolar binding affinities was accomplished by the combined use of pharmacophore- and receptor-guided approaches based on the structure of the physiological enzyme activator, diacylglycerol (DAG). Earlier use of the former approach, which was based on the structural equivalence of DAG and phorbol ester pharmacophores, identified a fixed template for the construction of a semirigid "recognition domain" that contained the three principal pharmacophores of DAG constrained into a lactone ring (DAG-lactones). In the present work, the pharmacophore-guided approach was refined to a higher level based on the X-ray structure of the C1b domain of PK-Cdelta complexed with phorbol-13-O-acetate. A systematic search that involved modifying the DAG-lactone template with a combination of linear or branched acyl and alpha-alkylidene chains, which functioned as variable hydrophobic "affinity domains", helped identify compounds that optimized hydrophobic contacts with a group of conserved hydrophobic amino acids located on the top half of the C1 domain where the phorbol binds. The hydrophilic/hydrophobic balance of the molecules was estimated by the octanol/water partition coefficients (log P) calculated according to a fragment-based approach. The presence of branched alpha-alkylidene or acyl chains was of critical importance to reach low nanomolar binding affinities for PK-C. These branched chains appear to facilitate important van der Waals contacts with hydrophobic segments of the protein and help promote the activation of PK-C through critical membrane interactions. Molecular modeling of these DAG-lactones into an empty C1b domain using the program AutoDock 2.4 suggests the existence of competing binding modes (sn-1 and sn-2) depending on which carbonyl is directly involved in binding to the protein. Inhibition of epidermal growth factor (EGF) binding, an indirect PK-C mediated response, was realized with some DAG-lactones at a dose 10-fold higher than with the standard phorbol-12, 13-dibutyrate (PDBU). Through the National Cancer Institute (NCI) 60-cell line in vitro screen, DAG-lactone 31 was identified as a very selective and potent antitumor agent. The NCI's computerized, pattern-recognition program COMPARE, which analyzes the degree of similarity of mean-graph profiles produced by the screen, corroborated our principles of drug design by matching the profile of compound 31 with that of the non-tumor-promoting antitumor phorbol ester, prostratin. The structural simplicity and the degree of potency achieved with some of the DAG-lactones described here should dispel the myth that chemical complexity and pharmacological activity go hand in hand. Even as a racemate, DAG-lactone 31 showed low namomolar binding affinity for PK-C and displayed selective antitumor activity at equivalent nanomolar levels. Our present approach should facilitate the generation of multiple libraries of structurally similar DAG-lactones to help exploit molecular diversity for PK-C and other high-affinity receptors for DAG and the phorbol esters. The success of this work suggests that substantially simpler, high-affinity structures could be identified to function as surrogates of other complex natural products.

The 5-(4-formyl-3,5-dimethoxyphenoxy)valeric acid (Barany) linker and its monomethoxy analog were applied to the Multipin method of solid phase synthesis. A comparative assessment of reductive amination and cleavage of these linkers under conditions of multiple synthesis indicated that both were applicable to a broad range of primary amines including aniline and 4-nitroaniline. Apart from the greater lability of the dimethoxy version under TFA cleavage, there was no observable advantage of one linker over the other within the described experiment.

When Pseudomonas oleovorans was grown on a mixture of 5-phenylvaleric acid, PVA, and nonanoic acid, NA, the reserve polyester produced included both a homopolymer and a copolymer. The homopolymer poly-3-hydroxy-5-phenylvalerate, PHPV, contained only 3-hydroxy-5-phenylvalerate units, while the copolymer contained the same long chain 3-hydroxyalkanoates as those present in the copolymer poly-3-hydroxynonanoate, PHN, which is produced from acid alone. The intracellular location of each of these polymers was determined by selective staining of the inclusion body granules with ruthenium tetraoxide and examination by transmission electron microscopy showed that both types of polyesters occurred in the same granule. PHN was present in the center of the granule, while PHPV accumulated around the PHN in the inclusion body. The proteins associated with the inclusion bodies were separated using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). In all cases, two different polymerase enzymes of molecular weight 59 and 55 KDa were present, indicating that the same polymerase enzyme system was responsible for the production of both PHN and PHPV. Attempts were made to produce a random copolymer containing both alkyl and phenylalkyl repeat units by varying the growth conditions, but a mixture of PHN and PHPV was always produced instead.

The synthesis of the polypropionate-derived pheromones sitophilate (1) and sitophilure (2) are described using an asymmetric aldol condensation as the key step to adduct 6; compound 6 was smoothly converted to the antipodes of each pheromone. This procedure can be expanded to more complicated structures with the same type of syn configuration such as stegobinone (3) and serricornin (4).

Purpose: Scar formation from the process of wound healing is mediated primarily by fibroblasts and is a major problem in ophthalmology in general and in glaucoma therapy in particular. Interactions between fibroblasts and glycoprotein components of the extracellular matrix (ECM) are among the major causes of scar formation. Recognition of ECM glycoproteins occurs via cell surface integrins that are specific for adhesion epitopes, such as the Arg-Gly-Asp (RGD-) containing amino acid sequence. The RGD sequence, which is present in several matrix and plasma proteins, including fibronectin (FN) and vitronectin, is involved in cell-ECM interactions that occur during inflammatory and homeostatic reactions. The present study was designed to examine the possibility of using RGD-mimetics as inhibitors of fibroblasts-FN interactions., Methods: Two nonpeptidic mimetics of RGD were designed and constructed, and their inhibitory effect on the adhesion of human tenon's capsule fibroblasts to FN was examined. SF-6,5 consisting of the carboxylate group of Asp and the guanidinium group of Arg divided by a linear atom spacer and a newly designed mimetic, designated NS-11, were examined herein., Results: The RGD mimetics, SF-6,5 and NS-11, but not an Arg-Gly-Glu (RGE) mimetic inhibited the adhesion of ocular fibroblasts to immobilized FN. SF-6,5 and NS-11 did not inhibit adhesion of the fibroblasts to laminin or spontaneous proliferation of fibroblasts. Trypsin pretreatment of the nonpeptidic RGD mimetics did not affect their ability to inhibit adhesion of the ocular fibroblasts to FN, whereas that of the RGD-containing peptide was abolished by the pretreatment., Conclusion: Nonpeptidic mimetics of RGD are attractive candidates for therapeutic agents to prevent the formation of scar tissue and related RGD-dependent pathologic events.

Rabbit muscle pyruvate kinase was irreverisbly inactivated by 5-chloro-4-oxopentanoic acid with a pKa of 9.2. The inhibition was time-dependent and was related to the 5-chloro-4-oxopentanoic acid concentration. Analysis of the kinetics of inhibition showed that the binding of the inhibitor showed positive co-operativity (n = 1.5 +/- 0.2). Inhibition of pyruvate kinase by 5-chloro-4-oxopentanoic acid was prevented by ligands which bind to the active site. Their effectiveness was placed in the order Mg2+ greater than phosphoenolpyruvate greater than ATP greater than ADP greater than pyruvate. Inhibitor-modified pyruvate kinase was unable to catalyse the detritiation of [3-(3)H]pyruvate in the ATP-promoted reaction, but it did retain 5-10% of the activity with either phosphate or arsenate as promoters. 5-Chlor-4-oxo-[3,5-(3)H]pentanoic acid was covalently bound to pyruvate kinase and demonstrated a stoicheiometry of 1 mol of inhibitor bound per mol of pyruvate kinase protomer. The incorporation of the inhibitor and the loss of enzyme was proportional. These results are discussed in terms of 5-chloro-4-oxopentanoic acid alkylating a functional group in the phosphoryl overlap region of the active site, and a model is presented in which this compound alkylates an active-site thiol in a reaction that is controlled by a more basic group at the active site.

A series of phenylenebis(oxy)bis[2,2-dimethylpentanoic acid]s have been synthesized and evaluated as potential hypolipidemic agents. Compound 18 (CI-924) was found to be the most potent compound in this series. In rats, compound 18 not only reduced low-density lipoprotein cholesterol but also increased high-density lipoprotein (HDL) cholesterol. Comparative studies in rats indicated 18 produced an equal elevation of HDL cholesterol at one-third of the dose required of gemfibrozil. Structure-activity relationships are discussed.

When 70-80-g male albino rats eat a diet furnishing daily requirement of valine for optimal growth (70 mumol/g) and all other nutrients ("complete diet"), they gain weight at an average rate of 3.0 g/100 g body wt/day. When valine is removed, they lose weight at an average 2.1 g/100 g body wt/day. The growth retardation is improved or corrected by adding valine to the diet, daily weight gain being proportional to dietary valine content over a range of 0-70 mumol/g. Addition of alpha-ketoisovaleric acid instead of valine to the valine-free diet also improves or corrects the growth failure. Percent efficiency of alpha-ketoisovaleric acid as a substitute for valine was calculated as: 100 x (micromole valine per gram diet required to produce specified growth response)/(micromole alpha-ketoisovaleric acid per gram diet required to produce the same response). Efficiency of the substitution is inversely related to dietary content of the keto analogue, being 80% when diet contains 17.5 mumol/g (molar equivalent of (1/4) the daily requirement of valine), and 37% when diet provides 140 mumol/g (molar equivalent of twice the daily requirement of valine).alpha-Hydroxyisovaleric acid also substitutes for valine. Efficiency of the substitution at the single ration tested, 70 mumol/g diet, is 45%, similar to that for the keto analogue under the same conditions. When [1-(14)C]alpha-ketoisovaleric acid is injected intravenously, 30-80% of the administered radioactivity is exhaled as (14)CO(2) within 24 h. This finding suggests that inefficiency of alpha-ketoisovaleric acid as a substitute for valine results in part from degradation of the keto acid to isobutyric acid by branched chain dehydrogenase-decarboxylase. Oral administration of neomycin, polymyxin, and bacitracin reduces efficiency of alpha-ketoisovaleric acid as a substitute for valine by (1/4)-(1/2). This effect suggests that transamination of the keto acid may be performed in part by gastrointestinal microbes.

In order to test for dopamine-receptor stimulating activity a new, sensitive biochemical screening method was designed. For behavioral studies and for determination of the duration of action on the compounds, motor activity measurements were used. O,O'-Dipivaloyl-N,N-dipropyldopamine (4) was the only derivative of a series of dipivaloyl-N,N-dialkyldopamines studied that showed any significant activity. However, the monopivaloyl ester 2-(3-pivaloyloxyphenyl)-N,N-dipropylethylamine (8) seemed to be more potent. The same relationship was found for the corresponding phenols, N,N-dipropyldopamine (3) and 2-(3-hydroxyphenyl)-N,N-dipropylethylamine (7), although both were more active than their pivaloyl esters.

In the reaction of 4-desmethylkhelline with ethyl alpha-bromobutyrate or alpha-bromovalerate we obtained alpha-[7-methyl-9-methoxy-5-oxo-furo[3,2-g] [1] benzopyranoxy-4]-butyric 2 and valeric 3 acids and later their dialkylaminoethylesters as hydrochlorides (2b--2, 3b--3e). Compounds 2c, 2e, 2f (Table 1) and 3e (Table 2) show a weak hypotensic activity. Moreover compound 2f possesses an antriarrhythmic activity.

Several 5-aryl-3-methylvaleric acid derivatives have been shown to be more potent hypolipidemic agents than the previously reported 5-(4-biphenylyl)-3-methylvaleric acid (1). The most active compound in this series was 5-(4-phenylsulfonylphenyl)-3-methylvaleric acid (10) which lowered serum cholesterol levels 45% and serum triglyceride levels 60% in normal rats. Significant lowering of the serum triglyceride levels was the predominant effect noted with most of the compounds tested.

Deficiency of biotin at the tissue level can be assessed indirectly by measuring the urinary excretion of 3-hydroxyisovaleric acid. This paper describes the application of an improved method of quantifying urinary 3-hydroxyisovaleric acid using unlabeled and uniformly deuterated 3-hydroxyisovaleric acid. These compounds were synthesized by a modification of the lithioacetic acid method for generation of beta-hydroxy acids. Elemental analysis, nuclear magnetic resonance, gas chromatographic and gas chromatographic/mass spectrometric data demonstrated that the compounds are greater than 95% pure. Mass spectrometry confirmed the identity of the unlabeled compound, demonstrated that the deuterated compound is uniformly labeled, and offered insight into the pattern of mass fragmentation. The method for determination of the concentration of 3-hydroxyisovaleric acid in rat urine uses gas chromatographic/mass spectrometric quantification of the di-trimethylsilyl derivative with the deuterated compound as the internal standard. Results provide evidence that this method is more accurate than a previously published method that did not utilize the unlabeled and deuterated standards.

The synthesis of the (+/-) 3-(4-biphenylyl)-3-hydroxybutanoic, pentanoic, hexanoic and isohexanoic acids, and their resolution in to enantiomers are described. The latter were submitted to preliminary assay for antiinflammatory activity: interesting results were obtained above all for the isohexanoic acid derivative.

1. Partially purified extracts of a Pseudomonas converted the meta ring-fission product of 4-methylcatechol into a compound having spectroscopic and chemical properties consistent with its being 2-oxohex-4-enoic acid. 2. Catechol and 3-methylcatechol were both metabolized to a compound that appeared to be 2-oxopent-4-enoic acid. 3. Solutions of norvaline and norleucine were prepared from these metabolites. 4. A reaction scheme is presented for the conversion of catechols into hydroxyoxo acids after meta ring-fission.

The metabolism of cholic acid by Arthrobacter simplex was investigated. This organism effected both ring a cleavage and elimination of the hydroxyl groups at C-7 and C-12 and gave a new metabolite, (4R)-4-[4alpha-(2-carboxyethyl)-3aalpha-hexahydro-7abeta-methyl-5-oxoindan-1beta-yl]valeric acid, which was isolated and identified through its partial synthesis. A degradative pathway of cholic acid into this metabolite is tentatively proposed, and the possibility that the proposed pathway could be extended to the cholic acid degradation by other microorganisms besides A. simplex is discussed. The possibility that the observed reactions in vitro could occur during the metabolism of bile acids in vivo is considered.