Biomaterial Database

Evidence for the essential histidine residue at the active site of glucose/xylose isomerase from Streptomyces. 1988

S M Gaikwad, and M W More, and H G Vartak, and V V Deshpande

Division of Biochemical Sciences, National Chemical Laboratory, Pune, India.

Modification of glucose/xylose isomerase from Streptomyces sp. NCIM 2730 by diethylpyrocarbonate (DEPC) or its photo-oxidation in presence of rose bengal or methylene blue caused rapid loss in its activity. The inactivation of the enzyme was accompanied by an increase in the absorbance at 240 nm and was reversed by hydroxylamine. Glucose and xylose but not Mg++ and Co++ afforded significant protection to the enzyme from inactivation by DEPC. Inactivation followed pseudo-first-order kinetics and modification of a single histidine residue per mole of enzyme was indicated.

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D008751	Methylene Blue	A compound consisting of dark green crystals or crystalline powder, having a bronze-like luster. Solutions in water or alcohol have a deep blue color. Methylene blue is used as a bacteriologic stain and as an indicator. It inhibits GUANYLATE CYCLASE, and has been used to treat cyanide poisoning and to lower levels of METHEMOGLOBIN.	Methylthionine Chloride,Swiss Blue,Basic Blue 9,Chromosmon,Methylene Blue N,Methylthioninium Chloride,Urolene Blue,Blue 9, Basic,Blue N, Methylene,Blue, Methylene,Blue, Swiss,Blue, Urolene
D010084	Oxidation-Reduction	A chemical reaction in which an electron is transferred from one molecule to another. The electron-donating molecule is the reducing agent or reductant; the electron-accepting molecule is the oxidizing agent or oxidant. Reducing and oxidizing agents function as conjugate reductant-oxidant pairs or redox pairs (Lehninger, Principles of Biochemistry, 1982, p471).	Redox,Oxidation Reduction
D002238	Carbohydrate Epimerases	Enzymes that catalyze the epimerization of chiral centers within carbohydrates or their derivatives. EC 5.1.3.	Carbohydrate Isomerases,Epimerases, Carbohydrate,Isomerases, Carbohydrate
D002384	Catalysis	The facilitation of a chemical reaction by material (catalyst) that is not consumed by the reaction.	Catalyses
D004047	Diethyl Pyrocarbonate	Preservative for wines, soft drinks, and fruit juices and a gentle esterifying agent.	Diethyl Dicarbonate,Diethyl Oxydiformate,Pyrocarbonic Acid Diethyl Ester,Diethylpyrocarbonate,Ethoxyformic Anhydride,Anhydride, Ethoxyformic,Dicarbonate, Diethyl,Oxydiformate, Diethyl,Pyrocarbonate, Diethyl
D004789	Enzyme Activation	Conversion of an inactive form of an enzyme to one possessing metabolic activity. It includes 1, activation by ions (activators); 2, activation by cofactors (coenzymes); and 3, conversion of an enzyme precursor (proenzyme or zymogen) to an active enzyme.	Activation, Enzyme,Activations, Enzyme,Enzyme Activations
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
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
D001665	Binding Sites	The parts of a macromolecule that directly participate in its specific combination with another molecule.	Combining Site,Binding Site,Combining Sites,Site, Binding,Site, Combining,Sites, Binding,Sites, Combining