Agmatinase-like family includes proclavaminic acid amidinohydrolase
This agmatinase subfamily contains bacterial and fungal/metazoan enzymes, including proclavaminic acid amidinohydrolase (PAH, EC 3.5.3.22) and Pseudomonas aeruginosa guanidinobutyrase (GbuA) and guanidinopropionase (GpuA). PAH hydrolyzes amidinoproclavaminate to yield proclavaminate and urea in clavulanic acid biosynthesis. Clavulanic acid is an effective inhibitor of beta-lactamases and is used in combination with amoxicillin to prevent the beta-lactam rings of the antibiotic from hydrolysis and, thus keeping the antibiotic biologically active. GbuA hydrolyzes 4-guanidinobutyrate (4-GB) into 4-aminobutyrate and urea while GpuA hydrolyzes 3-guanidinopropionate (3-GP) into beta-alanine and urea. Mutation studies show that significant variations in two active site loops in these two enzymes may be important for substrate specificity. This subfamily belongs to the ureohydrolase superfamily, which includes arginase, agmatinase, proclavaminate amidinohydrolase, and formiminoglutamase.