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Wheat gluten is a Pro-rich protein complex comprising glutenins and gliadins. Previous studies have reported that oral intake of enzymatic hydrolysates of gluten has beneficial effects, such as suppression of muscle injury and improvement of hepatitis. Here, we utilized ginger protease that preferentially cleaves peptide bonds with Pro at the P2position to produce a novel type of wheat gluten hydrolysate. Ginger protease efficiently hydrolyzed gluten, particularly under weak acidic conditions, to peptides with an average molecular weight of <600 Da. In addition, the gluten hydrolysate contained substantial amounts of tripeptides, including Gln-Pro-Gln, Gln-Pro-Gly, Gln-Pro-Phe, Leu-Pro-Gln, and Ser-Pro-Gln (e.g. 40.7 mg/g at pH 5.2). These gluten-derived tripeptides showed high inhibitory activity on dipeptidyl peptidase-IV with IC50values of 79.8, 70.9, 71.7, 56.7, and 78.9 μM, respectively, suggesting that the novel gluten hydrolysate prepared using ginger protease can be used as a functional food for patients with type 2 diabetes. Production of DPP-IV inhibitory tripeptides from gluten using ginger protease. [ABSTRACT FROM PUBLISHER]

Flavobacterium psychrophilum(F. psychrophilum) is the causative agent of bacterial cold-water disease (BCWD) that occurs in ayuPlecoglossus altivelis. Formalin-killed cell ofF. psychrophilumhas long been studied as an immersion vaccine for BCWD. In this study, we explored the possibility ofF. psychrophilumcollagenase (fpcol) for use as the immersion vaccine. BCWD convalescent ayu sera contained specific IgM antibodies against somaticF. psychrophilumand fpcol, meaning that fpcol is a promising antigen for the vaccine development. The recombinant fpcol was successfully expressed inEscherichia coliandBrevibacillus chosinensis(B. chosinensis). The culture supernatant of theB. chosinensiswas used as an immersion vaccine solution. The vaccinated ayu were then challenged by soaking intoF. psychrophilumculture. In two experimental groups, the relative percentages of survivals were 63 and 38%, respectively, suggesting that fpcol is promising as the immersion vaccine for ayu-BCWD. [ABSTRACT FROM PUBLISHER]

Bovine type I collagen consists of two α1 and one α2 chains, containing the internal triple helical regions and the N- and C-terminal telopeptides. In industries, it is frequently digested with porcine pepsin to produce a triple helical collagen without the telopeptides. However, the digestion mechanism is not precisely understood. Here, we performed a mass spectrometric analysis of the pepsin digest of the N-terminal telopeptide pQLSYGYDEKSTGISVP (1–16) in the α1 chain. When purified collagen was digested, pQLSYGY (1–6) and pQLSYGYDEKSTG (1–12) were identified, while DEKSTG (7–12) was not. When the N-terminal telopeptide mimetic synthetic peptide pQLSK(MOCAc)GYDEKSTGISK(Dnp)P-NH2was digested, pQLSK(MOCAc)GYDEKSTG (1–12) and ISK(Dnp)P-NH2(13−16) were readily identified, pQLSK(MOCAc)GY (1−6) and DEKSTGISK(Dnp)P-NH2(7−16) were weakly detected, and DEKSTG (7–12) was hardly identified. These results suggest that pepsin preferentially cleaves Tyr6–Asp7 and less preferentially Gly12–Ile13. They also suggest that the former cleavage requires native collagen structure, while the latter cleavage does not. Pepsin preferentially cleaves Tyr6–Asp7 and less preferentially Gly12–Ile13. The former cleavage requires native collagen structure, while the latter cleavage does not. [ABSTRACT FROM PUBLISHER]

The collagenase activity and thefpcolgene were examined inFlavobacterium psychrophilumisolates from cold-water disease (CWD)-affected ayu,Plecoglossus altivelis. Collagenase expression was closely related to the accumulated mortality of CWD-affected ayu. RT-qPCR and bacterial challenge experiments showed thatF. psychrophilumayu isolate WA-1 expressed thefpcolgene more actively and was more virulent than ayu isolate WA-2. The amago (Oncorhynchus masou) isolate WB-1, which possesses a pseudo-fpcolgene, was not harmful to ayu. Hitherto, the well-studied metalloproteases Fpp1 and Fpp2 have been considered virulence factors. However, the most virulent isolate against ayu (WA-1) showed no Fpp activity because of a deletion mutation or an insertion of a transposon in thefppgenes. The less virulent WA-2 isolate showed only Fpp1 activity. Taken together, these results suggest that collagenolytic activity, but not Fpp activity, is related to the virulence ofF. psychrophilumisolates in CWD-affected ayu. Comparative study ofFlavobacterium psychrophilumisolates from ayu and amago suggests that the collagenase is one of the pathogenic factors for ayu. [ABSTRACT FROM PUBLISHER]

The article discusses the results of a study which examined the improvement in the physical and biochemical characteristics of a pepsin-solubilized collagen (PSC) membrane by conjugating with soluble egg shell membrane protein (SEP). The conjugated membrane was found to have thicker collagen fibrils and higher stability than PSC membrane alone. An SEP-PSC coating accelerated the growth of fibroblasts. However, the cell growth of keratinocytes did not change.

Investigates the effects of (-)-epigallocatechin gallate (EGCG) on the contraction of floating collagen gel by fibroblasts. Interaction between EGCG and platelet-derived growth factor; Affinity chromatography; Enzyme-linked immunoassay; Mechanism of inhibition of collagen gel contraction by EGCG.