Molecular identification of omega-amidase, the enzyme that is functionally coupled with glutamine transaminases, as the putative tumor suppressor Nit2.
Our purpose was to identify the sequence of omega-amidase, which hydrolyses the amide group of alpha-ketoglutaramate, a product formed by glutamine transaminases. In the Bacillus subtilis genome, the gene encoding a glutamine transaminase (mtnV) is flanked by a gene encoding a putative 'carbon-nitrogen hydrolase'. The closest mammalian homolog of this putative bacterial omega-amidase is 'nitrilase 2', whose size and amino acid composition were in good agreement with those reported for purified rat liver omega-amidase. Mouse nitrilase 2 was expressed in Escherichia coli, purified and shown to catalyse the hydrolysis of alpha-ketoglutaramate and other known substrates of omega-amidase. No such activity was observed with mouse nitrilase 1. We conclude that mammalian nitrilase 2 is omega-amidase.
Jaisson
Stéphane
S
Laboratory of Physiological Chemistry, De Duve Institute, Université Catholique de Louvain, B-1200 Brussels, Belgium.
Veiga-da-Cunha
Maria
M
Van Schaftingen
Emile
E
D000581:Amidohydrolases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D000619:Aminohydrolases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D001412:Bacillus subtilis / Q000201:enzymology / Q000235:genetics; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D015153:Blotting, Western; D002460:Cell Line; D019295:Computational Biology; D030541:Databases, Genetic; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D016680:Genome, Bacterial / Q000235:genetics; D006801:Humans; D007656:Ketoglutaric Acids / Q000378:metabolism; D051379:Mice; D008957:Models, Genetic; D008969:Molecular Sequence Data; D017386:Sequence Homology, Amino Acid; D000637:Transaminases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
D001426:Bacterial Proteins; D007656:Ketoglutaric Acids; C008230:alpha-ketoglutaramate; D000637:Transaminases; C020656:glutamine-pyruvate aminotransferase; D000581:Amidohydrolases; C047679:omega-amidase; D000619:Aminohydrolases