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Cyanogen as a selective probe for carbonic anhydrase hydrolase activity
Author(s) -
Karagözler A. A.,
Ghenbot G.,
Day R. A.
Publication year - 1993
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.360330417
Subject(s) - chemistry , carbonic anhydrase , hydrolase , active site , enzyme , stereochemistry , covalent bond , cyanogen bromide , carbonic anhydrase ii , acetazolamide , biochemistry , peptide sequence , organic chemistry , medicine , anesthesia , gene
The salt bridge probe cyanogen (ethanedinitrile, C 2 N 2 ; NC–‐CN) inhibits the bovine carbonic anhydrase (EC 4.2.1.1.) hydrolase activity toward various types of esters without significant effect on its hydrolyase activity. Two sets of pyridine derivatives that were isosteric substrates for the two activities were differentially affected. Acetazolamide and salamide are reversible inhibitors of the enzyme; only salamide affords protection of the hydrolase activity against the action of C 2 N 2 . Since each is known to bind in different positions within the active site, the selective effect of salamide may arise from its position covering one CO 2 site as well as a site important for hydrolase activity. The C 2 N 2 concentration dependence of the time course of hydrolase inhibition is consistent with the existence of a high C 2 N 2 affinity site with slow covalent change and a second site with lower C 2 N 2 affinity, but higher rate of covalent modification of the enzyme. © 1993 John Wiley & Sons, Inc.