title: Heparin as an inhibitor of L-arginyl-tRNA: protein arginyltransferase.
abstract: Heparin, a naturally occurring mucopolysaccharide, was found to be a potent inhibitor of L-arginyl-tRNA:protein arginyltransferase [EC 2.3.2.8]. It was demonstrated that heparin was not an acceptor of arginine, but an inhibitor competing with arginyl-tRNA. The Ki value of heparin was 1.5 microM, while the Km value of arginyl-tRNA was 0.5 microM. The inhibition was specific for heparin among the mucopolysaccharides examined. The N-sulfate groups were indispensable for heparin to inhibit the arginyltransferase activity. Arginyltransferases from various origins were commonly inhibited by heparin. Polyamines such as spermine and spermidine were also found to inhibit the transferase activity, competing with arginyl-tRNA. An extremely high specific activity of 2.3 mumol/min/mg was achieved by the application of these inhibitors to the purification of the transferase by affinity chromatography.
mesh_terms: D000217:Acyltransferases / Q000037:antagonists & inhibitors* / Q000302:isolation & purification; D019881:Aminoacyltransferases; D000818:Animals; D006493:Heparin / Q000494:pharmacology*; D007668:Kidney / Q000201:enzymology; D007700:Kinetics; D010441:Peptide Chain Elongation, Translational / Q000187:drug effects*; D013552:Swine
chemical_list: D006493:Heparin; D000217:Acyltransferases; D019881:Aminoacyltransferases; C019727:arginyltransferase