Biomaterial Database

Radiation-induced inactivation of flavocytochrome b2 in dilute aqueous solution. 1995

D Bhattacharya, and A Saha, and P C Mandal

Nuclear Chemistry Division, Saha Institute of Nuclear Physics, Calcutta, India.

Effect of gamma radiation on flavocytochrome b2 in dilute aqueous solution was studied. A study of the effect of the radiolytically produced inorganic free-radical anions such as I2.-, Br2.- and (SCN)2.- on the enzyme activity indicates the involvement of cysteine and tyrosine residues in the catalytic activity of flavocytochrome b2. The changes in kinetic parameters, i.e., Michaelis-Menten constant Km and maximal velocity Vmax, due to irradiation under different conditions suggest that radiation induced enzyme inactivation is the result of destruction of active-site residues as well as modification of the substrate binding site. Fluorescence studies of unirradiated and irradiated enzyme reveal that FMN (flavin mononucleotide) is inaccessible to water radicals.

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D007770	L-Lactate Dehydrogenase	A tetrameric enzyme that, along with the coenzyme NAD+, catalyzes the interconversion of LACTATE and PYRUVATE. In vertebrates, genes for three different subunits (LDH-A, LDH-B and LDH-C) exist.	Lactate Dehydrogenase,Dehydrogenase, L-Lactate,Dehydrogenase, Lactate,L Lactate Dehydrogenase
D011193	Potassium Iodide	An inorganic compound that is used as a source of iodine in thyrotoxic crisis and in the preparation of thyrotoxic patients for thyroidectomy. (From Dorland, 27th ed)	Antistrumin,Ioduro Potasico Rovi,Iosat,Jod beta,Jodetten Henning,Jodgamma,Jodid,Jodid Hexal,Jodid Verla,Jodid dura,Jodid-ratiopharm,Mono-Jod,Pima,SSKI,Thyro-Block,Thyroprotect,Iodide, Potassium,Jodid ratiopharm,Mono Jod,Thyro Block
D001965	Bromides	Salts of hydrobromic acid, HBr, with the bromine atom in the 1- oxidation state. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)	Bromide
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
D005609	Free Radicals	Highly reactive molecules with an unsatisfied electron valence pair. Free radicals are produced in both normal and pathological processes. Free radicals include reactive oxygen and nitrogen species (RONS). They are proven or suspected agents of tissue damage in a wide variety of circumstances including radiation, damage from environment chemicals, and aging. Natural and pharmacological prevention of free radical damage is being actively investigated.	Free Radical
D012441	Saccharomyces cerevisiae	A species of the genus SACCHAROMYCES, family Saccharomycetaceae, order Saccharomycetales, known as "baker's" or "brewer's" yeast. The dried form is used as a dietary supplement.	Baker's Yeast,Brewer's Yeast,Candida robusta,S. cerevisiae,Saccharomyces capensis,Saccharomyces italicus,Saccharomyces oviformis,Saccharomyces uvarum var. melibiosus,Yeast, Baker's,Yeast, Brewer's,Baker Yeast,S cerevisiae,Baker's Yeasts,Yeast, Baker
D012996	Solutions	The homogeneous mixtures formed by the mixing of a solid, liquid, or gaseous substance (solute) with a liquid (the solvent), from which the dissolved substances can be recovered by physical processes. (From Grant & Hackh's Chemical Dictionary, 5th ed)	Solution
D013050	Spectrometry, Fluorescence	Measurement of the intensity and quality of fluorescence.	Fluorescence Spectrophotometry,Fluorescence Spectroscopy,Spectrofluorometry,Fluorescence Spectrometry,Spectrophotometry, Fluorescence,Spectroscopy, Fluorescence
D013861	Thiocyanates	Organic derivatives of thiocyanic acid which contain the general formula R-SCN.	Rhodanate,Rhodanates