Catalysis by human leukocyte elastase: III. Steady-state kinetics for the hydrolysis of p-nitrophenyl esters.
Steady-state kinetic parameters were determined at pH 7.4 and 25 degrees C for the human leukocyte elastase-catalyzed hydrolysis of several N-carbobenzoxy-L-amino acid p-nitrophenyl esters. The substrate specificity for these esters was quite broad, and included the Gly, Phe, and Tyr derivatives. Together with reports of a much narrower P-1 specificity for peptide-based substrates, these results suggest that interactions remote from the scissle bond between enzyme and substrate regulate primary specificity. Also, it was found that kc and kc/Km did not exhibit the same dependence on substrate structure. This is interpreted to suggest that there are significant differences in P-1 specificity between acylation and deacylation for leukocyte elastase-catalyzed reactions.
D002384:Catalysis; D004952:Esters / Q000378:metabolism; D006801:Humans; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D007700:Kinetics; D007962:Leukocytes / Q000201:enzymology*; D009596:Nitrophenols / Q000378:metabolism*; D010196:Pancreatic Elastase / Q000097:blood* / Q000378:metabolism; D013379:Substrate Specificity
D004952:Esters; D009596:Nitrophenols; D010196:Pancreatic Elastase