Saccharomyces cerevisiae N-terminal amidase NTA1, and related proteins (class 3 nitrilases)
Saccharomyces cerevisiae NTA1 functions in the N-end rule protein degradation pathway. It specifically deaminates the N-terminal asparagine and glutamine residues of substrates of this pathway, to aspartate and glutamate respectively, these latter are the destabilizing residues. This subgroup belongs to a larger nitrilase superfamily comprised of nitrile- or amide-hydrolyzing enzymes and amide-condensing enzymes, which depend on a Glu-Lys-Cys catalytic triad. This superfamily has been classified in the literature based on global and structure based sequence analysis into thirteen different enzyme classes (referred to as 1-13), this subgroup corresponds to class 3.