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The catalytic mechanism of amidase also involves nitrile hydrolysis
Author(s) -
Kobayashi Michihiko,
Goda Masahiko,
Shimizu Sakayu
Publication year - 1998
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(98)01406-9
Subject(s) - amidase , rhodococcus rhodochrous , chemistry , benzonitrile , nitrile , hydrolysis , nitrilase , nitrile hydratase , amide , catalysis , peptide bond , organic chemistry , medicinal chemistry , stereochemistry , enzyme , rhodococcus
The amidase from Rhodococcus rhodochrous J1, which hydrolyzes an amide to an acid and ammonium, was surprisingly found to catalyze the hydrolytic cleavage of the C‐N triple bond in a nitrile to form an acid and ammonium stoichiometrically. The amidase exhibited a K m of 3.26 mM for benzonitrile in contrast to that of 0.15 mM for benzamide as the original substrate, but the V max for benzonitrile was about 1/6000 of that for benzamide. A mutant amidase containing alanine instead of Ser 195 , which is essential for amidase catalytic activity, showed no nitrilase activity, demonstrating that this residue plays a crucial role in the hydrolysis of nitriles as well as amides.