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A note on the enzymic action and biosynthesis of a nitrile‐hydratase from a Brevibacterium sp.
Author(s) -
Bui K.,
Maestracci M.,
Thiery A.,
Arnaud A.,
Galzy P.
Publication year - 1984
Publication title -
journal of applied bacteriology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 0021-8847
DOI - 10.1111/j.1365-2672.1984.tb02373.x
Subject(s) - nitrile hydratase , nitrile , chemistry , acrylonitrile , nitrilase , cyanide , substrate (aquarium) , amidase , brevibacterium , enzyme , biosynthesis , bioconversion , azotobacter vinelandii , biochemistry , alcaligenes faecalis , stereochemistry , organic chemistry , bacteria , nitrogenase , microorganism , fermentation , biology , nitrogen , ecology , genetics , nitrogen fixation , copolymer , polymer
The effect of different compounds on the enzymic action of the nitrile‐hydratase used for the bioconversion of nitriles was studied. An excess of acrylonitrile as a substrate was shown to inhibit the activity of the enzyme. This inhibition occurred only at relatively high substrate concentrations (0.2 mol/l or more). The nitrile bioconversion products (acrylamide, propionamide) and their structural analogues (acrylic acid, thioacetamide) were shown to inhibit the enzyme competitively. The most important inhibition found was that of cyanide (K i = 0.004 mol/l), a break down product of some nitriles. By using an acetamidase‐negative mutant, amides were shown to inhibit biosynthesis of nitrile‐hydratase. An identical result was obtained with thioacetamide, a non‐substrate compound for acetamidase. This compound repressed the biosynthesis of nitrile‐hydratase by both the wild type and the acetamidase‐negative mutant to the same extent.