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Michaelis complexes of porcine pancreatic elastase with 7‐[(alkylcarbamoyl)amino]‐4‐chloro‐3‐ethoxyisocoumarins: Translational sampling of inhibitor position and kinetic measurements
Author(s) -
Plaskon R. Richard,
Kam ChihMin,
Burgess Edward M.,
Powers James C.,
Suddath F. L.
Publication year - 1992
Publication title -
proteins: structure, function, and bioinformatics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.699
H-Index - 191
eISSN - 1097-0134
pISSN - 0887-3585
DOI - 10.1002/prot.340130207
Subject(s) - michaelis–menten kinetics , pancreatic elastase , chemistry , covalent bond , elastase , serine , stereochemistry , enzyme , biochemistry , combinatorial chemistry , organic chemistry , enzyme assay
A step leading to the formation of the covalent complexes between porcine pancreatic elastase (PPE) and 7‐[(alkylcarbamoyl)amino]‐4‐chloro‐3‐ethoxyisocoumarins (alkylHNCO‐EICs) is the formation of the non‐covalent Michaelis complex. No average structures are available for the Michaelis complexes of PPE with alkylHNCO‐EICs. We present the results of an initial step in obtaining these structures and have determined kinetic constants as well. The kinetic results indicate that formation of the Michaelis complex is what differentiates the effectiveness of these inhibitors in inactivating PPE. The structural and kinetic results together suggest that the structure of the Michaelis complex is necessary for the design of potent alkylHNCO‐EIC inhibitors of PPE. Two novel alkylHNCO‐EICs are predicted to be the best inhibitors of this series. An alternate mechanism for serine protease inhibition is also proposed. Evidence for, and studies that may add support to, the hypothesized mechanism are discussed. © 1992 Wiley‐Liss, Inc.