Biomaterial Database

Inactivation of human liver arginase by Woodward's reagent K: evidence for reaction with His141. 2004

Nelson Carvajal, and Elena Uribe, and Vasthi López, and Mónica Salas

Departamento de Biología Molecular, Facultad de Ciencias Biológicas, Universidad de Concepción, Casilla 160-C, Concepción, Chile. ncarvaja@udec.cl

Human liver arginase (EC 3.5.3.1) was totally inactivated by incubation with Woodward's reagent K (WRK). The inactivation followed pseudo-first-order kinetics, and the order of the inactivation was close to 1, consistent with reaction of one molecule of WRK with one subunit molecule for inactivation. The effect was totally reversed by 0.5 M hydroxylamine, and reactivated species were inactivated again by a second incubation with WRK. The pH dependence of the pseudo--first-order rate constants of inactivation indicated the participation of a ionizable residue with a pKa of 6.3 at 25 degrees C. Replacement of His141 with phenylalanine rendered the enzyme totally resistant to the inactivation. We conclude that His141 is the residue whose chemical modification with WRK inactivates the enzyme.

UI	MeSH Term	Description	Entries
D007555	Isoxazoles	Azoles with an OXYGEN and a NITROGEN next to each other at the 1,2 positions, in contrast to OXAZOLES that have nitrogens at the 1,3 positions.	Isoxazole
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D008099	Liver	A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.	Livers
D004305	Dose-Response Relationship, Drug	The relationship between the dose of an administered drug and the response of the organism to the drug.	Dose Response Relationship, Drug,Dose-Response Relationships, Drug,Drug Dose-Response Relationship,Drug Dose-Response Relationships,Relationship, Drug Dose-Response,Relationships, Drug Dose-Response
D006639	Histidine	An essential amino acid that is required for the production of HISTAMINE.	Histidine, L-isomer,L-Histidine,Histidine, L isomer,L-isomer Histidine
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D006863	Hydrogen-Ion Concentration	The normality of a solution with respect to HYDROGEN ions; H+. It is related to acidity measurements in most cases by pH	pH,Concentration, Hydrogen-Ion,Concentrations, Hydrogen-Ion,Hydrogen Ion Concentration,Hydrogen-Ion Concentrations
D001119	Arginase	A ureahydrolase that catalyzes the hydrolysis of arginine or canavanine to yield L-ornithine (ORNITHINE) and urea. Deficiency of this enzyme causes HYPERARGININEMIA. EC 3.5.3.1.	Arginase A1,Arginase A4,Hepatic Proliferation Inhibitor,Liver Immunoregulatory Protein,Liver-Derived Inhibitory Protein,Liver-Derived Lymphocyte Proliferation Inhibiting Protein,Immunoregulatory Protein, Liver,Inhibitor, Hepatic Proliferation,Inhibitory Protein, Liver-Derived,Liver Derived Inhibitory Protein,Liver Derived Lymphocyte Proliferation Inhibiting Protein,Proliferation Inhibitor, Hepatic,Protein, Liver Immunoregulatory,Protein, Liver-Derived Inhibitory
D013997	Time Factors	Elements of limited time intervals, contributing to particular results or situations.	Time Series,Factor, Time,Time Factor