haloacid dehalogenase (HAD)-like 5'-nucleotidases similar to the Pseudomonas aeruginosa PA0065
5'-nucleotidases dephosphorylate nucleoside 5'-monophosphates to nucleosides and inorganic phosphate. Purified Pseudomonas aeruginosa PA0065 displayed high activity toward 5'-UMP and 5'-IMP, significant activity against 5'-XMP and 5'-TMP, and low activity against 5'-CMP. This family belongs to the haloacid dehalogenase-like (HAD) hydrolases, a large superfamily of diverse enzymes that catalyze carbon or phosphoryl group transfer reactions on a range of substrates, using an active site aspartate in nucleophilic catalysis. Members of this superfamily include 2-L-haloalkanoic acid dehalogenase, azetidine hydrolase, phosphonoacetaldehyde hydrolase, phosphoserine phosphatase, phosphomannomutase, P-type ATPases and many others. HAD hydrolases are found in all three kingdoms of life, and most genomes are predicted to contain multiple HAD-like proteins. Members possess a highly conserved alpha/beta core domain, and many also possess a small cap domain, the fold and function of which is variable. HAD hydrolases are sometimes referred to as belonging to the DDDD superfamily of phosphohydrolases.