title: An essential arginine residue in human prostatic acid phosphatase.
abstract: Treatment of human prostatic acid phosphatase (orthophosphoric-monoester phosphohydrolase (acid optimum), EC 3.1.3.2) with either of the arginine-specific modifiers 2,3-butanedione or 1,2-cyclohexanedione in borate buffer at pH 8.1 leads to loss of activity. The inactivation by cyclohexanedione can be partially reversed by 0.2 M hydroxylamine. The rate of inactivation by both modifiers is decreased in the presence of the competitive inhibitors L-(+)-tartrate or inorganic phosphate but not in the presence of the non-inhibitor D-(-)-tartrate. Amino acid analysis of modified acid phosphatase indicates that only arginines are modified and that L-(+)-tartrate protects at least two arginyl residues from modification. A likely role of these arginyl residues is their involvement in binding the negatively charged phosphate group of the substrate.
mesh_terms: D000135:Acid Phosphatase / Q000378:metabolism; D000596:Amino Acids / Q000032:analysis; D001120:Arginine; D001665:Binding Sites; D002074:Butanones / Q000494:pharmacology; D003512:Cyclohexanones / Q000494:pharmacology; D006801:Humans; D007700:Kinetics; D008297:Male; D011467:Prostate / Q000201:enzymology*
chemical_list: D000596:Amino Acids; D002074:Butanones; D003512:Cyclohexanones; D001120:Arginine; D000135:Acid Phosphatase