Kinetics of Hydrolysis of a New Peptide Substrate Containing p-Guanidino-L-phenylalanine by Trypsin and Thrombin

概要

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A new peptide substrate containing p-guanidine-L-phenylalanine, N^α-benzoyl-L-phenylalanyl-L-prolyl-p-guanidino-L-phenylalanine p-nitroanilide (Bz-Phe-Pro-GPA-pNA), was synthesized, and the rates of hydrolyses of this substrate by bovine trypsin and thrombin were compared with those of the corresponding arginine peptide substrate (Bz-Phe-Pro-GPA-pNA). The specificity constants (k_<cat>/K_m) for the hydrolysis of GPA-peptide by the two enzymes were much smaller than those for Arg-peptide. Remarkably low k_<cat> values were found in the hydrolyses of GPA-peptide by the two enzymes compared with the values in those of Arg-peptide. The effect of the peptide chain elongation was observed in the hydrolysis of GPA-peptide by thrombin, while it was not in the case of trypsin, suggesting that the subsite of trypsin is very different from that of thrombin. GPA-peptide was ascertained to be a useful peptide substrate to study the subsite specificities of trypsin-like enzymes.
公益社団法人日本薬学会の論文
1986-03-25