CPA (EC 220.127.116.11, also known as N-carbamoylputrescine amidase and carbamoylputrescine hydrolase) converts N-carbamoylputrescine to putrescine, a step in polyamine biosynthesis in plants and bacteria. This subgroup includes Arabidopsis thaliana CPA, also known as nitrilase-like 1 (NLP1), and Pseudomonas aeruginosa AguB. 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 11. Members of this superfamily generally form homomeric complexes, the basic building block of which is a homodimer; P. aeruginosa AugB is a homohexamer, Arabidopsis thaliana NLP1 is a homooctomer.