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Seryl-histidine dipeptide (Ser-His) has been recognized as the shortest peptide with hydrolysis cleavage activity; however, its protein cleavage spectrum has not yet been fully explored. Here, four differently folded proteins were treated with Ser-His, and the digestion products were evaluated with high-resolution mass spectrometry. The cleavage efficiency and cleavage propensity of Ser-His against these protein substrates were calculated at both the primary and secondary sequence levels. The above experiments show that Ser-His cleaves a broad spectrum of substrate proteins of varying secondary structures. Moreover, Ser-His could cleave at all 20 amino acids with different efficiencies according to the protein, which means that Ser-His has the original digestion function of serine proteases. Furthermore, we collected and compared the catalytic sites and cleavage sites of 340 extant serine proteases derived from 17 representative organisms. A consensus motif Ser-[X]-His was identified as the major pattern at the catalytic sites of serine proteases from all of the organisms represented except Danio rerio, which uses Ser-Lys instead. This finding indicates that Ser-His is the core component of the serine protease catalytic site. Moreover, our analysis revealed that the cleavage sites of modern serine proteases have become more specific over the evolutionary history of this family. Based on the above analysis results, it could be found that Ser-His is likely the original serine protease and maybe the evolutionary core of modern serine proteases. [ABSTRACT FROM AUTHOR]

Objective To investigate the value of HAT and SEDAN score scales in predicting hemorrhagic transformation (HT) following the recombinant tissue - type plasminogen activator (rt - PA) intravenous thrombolysis in acute ischemic stroke patients and risk factors affecting HT. Methods A total of 143 patients with acute ischemic stroke underwent rt-PA intravenous thrombolysis within 4.50 h of onset and their clinical data were collected. According to head CT after thrombolysis, patients were divided into HT group (18 cases) and non-HT group (125 cases). Single factor analysis was used to assess differences in HAT and SEDAN score scales and related risk factors of ischemic stroke in 2 groups, and further Logistic regression analysis was used to investigate independent predictors of HT. Receiver operating characteristic (ROC) curve was used to evaluate the sensitivity and specificity of HAT and SEDAN score scales in predicting HT. Results Univariate Logistic regression analysis showed that history of atrial fibrillation (AF), admission systolic blood pressure (SBP), admission blood glucose level, early low density of head CT, thrombolytic time window, National Institute of Health Stroke Scale (NIHSS), HAT and SEDAN scores were all risk factors for HT after thrombolysis (P < 0.05, for all). Multivariate Logistic regression analysis showed that history of AF (OR = 1.677, 95% CI: 1.332-2.111; P = 0.000), admission SBP (OR = 1.102, 95% CI: 1.009-1.204; P = 0.031), admission blood glucose level (OR = 1.870, 95% CI: 1.119-3.125; P = 0.017), thrombolysis time window (OR = 1.030, 95%CI: 1.009-1.052; P = 0.005), NIHSS score (OR = 1.574, 95%CI: 1.186-2.090; P = 0.002), HAT score (OR = 2.515, 95%CI: 1.273-4.970; P = 0.008) and SEDAN score (OR = 2.413, 95%CI: 1.123-5.185; P = 0.024) were risk factors for HT after thrombolysis. ROC curve analysis showed that HAT score could predict HT with 94.40% sensitivity and 41.60% specificity, and area under curve (AUC) was 0.70. SEDAN score could predict HT with 94.40% sensitivity and 65.62% specificity, and AUC was 0.77. Conclusions History of AF, admission SBP, admission blood glucose level, thrombolysis time window, NIHSS, HAT and SEDAN score scales were independent risk factors for hemorrhagic transformation after intravenous thrombolysis for treating ischemic stroke, while SEDAN score had high predictive value. [ABSTRACT FROM AUTHOR]

A gold-catalyzed intermolecular alkyne oxidation for the preparation of 3-coumaranones has been developed. Using 8-isopropylquinoline N-oxides as oxidants, the reactions of o-ethynylanisoles afford versatile 3-coumaranones in moderate to good isolated yields. The synthetic utility of this chemistry is also indicated by the synthesis of the natural product sulfuretin. [ABSTRACT FROM AUTHOR]

A reaction built for two: A novel gold ‐ catalyzed tandem cycloisomerization/dimerization of chiral homopropargyl sulfonamides has been developed. The reaction provides ready access to functionalized pyrrolidines in mostly good to excellent yields. Notably, excellent diastereoselectivities (>50:1) were also achieved in all cases. [ABSTRACT FROM AUTHOR]

A gold-catalyzed intermolecular alkyne oxidation for the preparation of 3-coumaranones has been developed. Using 8-isopropylquinoline N-oxides as oxidants, the reactions of o-ethynylanisoles afford versatile 3-coumaranones in moderate to good isolated yields. The synthetic utility of this chemistry is also indicated by the synthesis of the natural product sulfuretin., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)