Biomaterial Database

The functional involvement of Lys-38 in the heavy subunit of rat kidney gamma-glutamylcysteine synthetase: chemical modification and mutagenesis studies. 1996

L S Chang

Department of Biochemistry, Kaohsiung Medical College, Taiwan.

Rat kidney gamma-glutamylcysteine synthetase (gamma GCS) was inactivated by reaction with trinitrobenzene sulfonate (TNBS), and the reaction followed pseudo-first-order kinetics. Inactivation kinetics revealed that only one of the amino acid residues modified by TNBS was essential for gamma GCS activity. The addition of 10 mM Mg2+ to the TNBS inactivation reaction resulted in a 16-fold increase in the rate of inactivation. Chromatographic analysis on the tryptic hydrolyzates of trinitrophenylated (TNP) derivatives showed that Lys-38 in the gamma GCS heavy subunit was significantly modified in the presence of Mg2+. In contrast to small changes in the catalytic properties observed by mutation of Lys-38 to Arg, the mutants K38N and K38E had a marked decrease in enzymatic activity and about twofold increase in Km for glutamate. These results suggest that the positively charged Lys-38 may be involved in the binding of glutamate to gamma GCS.

UI	MeSH Term	Description	Entries
D007202	Indicators and Reagents	Substances used for the detection, identification, analysis, etc. of chemical, biological, or pathologic processes or conditions. Indicators are substances that change in physical appearance, e.g., color, at or approaching the endpoint of a chemical titration, e.g., on the passage between acidity and alkalinity. Reagents are substances used for the detection or determination of another substance by chemical or microscopical means, especially analysis. Types of reagents are precipitants, solvents, oxidizers, reducers, fluxes, and colorimetric reagents. (From Grant & Hackh's Chemical Dictionary, 5th ed, p301, p499)	Indicator,Reagent,Reagents,Indicators,Reagents and Indicators
D007668	Kidney	Body organ that filters blood for the secretion of URINE and that regulates ion concentrations.	Kidneys
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
D008239	Lysine	An essential amino acid. It is often added to animal feed.	Enisyl,L-Lysine,Lysine Acetate,Lysine Hydrochloride,Acetate, Lysine,L Lysine
D008969	Molecular Sequence Data	Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.	Sequence Data, Molecular,Molecular Sequencing Data,Data, Molecular Sequence,Data, Molecular Sequencing,Sequencing Data, Molecular
D011994	Recombinant Proteins	Proteins prepared by recombinant DNA technology.	Biosynthetic Protein,Biosynthetic Proteins,DNA Recombinant Proteins,Recombinant Protein,Proteins, Biosynthetic,Proteins, Recombinant DNA,DNA Proteins, Recombinant,Protein, Biosynthetic,Protein, Recombinant,Proteins, DNA Recombinant,Proteins, Recombinant,Recombinant DNA Proteins,Recombinant Proteins, DNA
D002413	Cations, Divalent	Positively charged atoms, radicals or groups of atoms with a valence of plus 2, which travel to the cathode or negative pole during electrolysis.	Divalent Cations
D004274	DNA, Recombinant	Biologically active DNA which has been formed by the in vitro joining of segments of DNA from different sources. It includes the recombination joint or edge of a heteroduplex region where two recombining DNA molecules are connected.	Genes, Spliced,Recombinant DNA,Spliced Gene,Recombinant DNA Research,Recombination Joint,DNA Research, Recombinant,Gene, Spliced,Joint, Recombination,Research, Recombinant DNA,Spliced Genes
D005260	Female		Females
D005721	Glutamate-Cysteine Ligase	One of the enzymes active in the gamma-glutamyl cycle. It catalyzes the synthesis of gamma-glutamylcysteine from glutamate and cysteine in the presence of ATP with the formation of ADP and orthophosphate. EC 6.3.2.2.	gamma-Glutamyl-Cysteine Synthetase,Glutamylcysteine Synthetase,Glutamate Cysteine Ligase,Ligase, Glutamate-Cysteine,Synthetase, Glutamylcysteine,Synthetase, gamma-Glutamyl-Cysteine,gamma Glutamyl Cysteine Synthetase