Biomaterial Database

Correlation between glutathione and stimulation of the pentose phosphate cycle in situ in Chinese hamster ovary cells exposed to hydrogen peroxide. 1996

E Przybytkowski, and D A Averill-Bates

Département de chimie, Université du Québec à Montréal, Canada.

The effect of glutathione on stimulation of pentose phosphate cycle activity during oxidative challenge was evaluated in intact Chinese hamster ovary cells in situ. Glutathione was depleted to varying levels with L-buthionine-[S,R] sulfoximine. The level of stimulation of pentose phosphate cycle activity by exogenous H2O2 (4 mumol/10(7) cells) was dependent on the time of pretreatment with L-buthionine-[S,R] sulfoximine and was proportional to the total glutathione concentration. This was not related to the amount of GSSG, since its level was exceedingly low under conditions where H2O2 stimulated pentose phosphate cycle activity. The amount of GSSG in cells increased after exposure to 10-fold higher concentrations of H2O2 under conditions where there was no stimulation of pentose phosphate cycle activity above the basal level. Paraquat caused stimulation of pentose phosphate cycle activity which was independent of L-buthionine-[S,R] sulfoximine pretreatment and of the glutathione content of cells. The stimulatory effects of both oxidants on pentose phosphate cycle activity appeared to be independent of glutathione reductase activity since they were unaffected in cells treated with 1,3-bis(2-chloroethyl)-1-nitrosourea. The inhibitory effect of L-buthionine-[S,R] sulfoximine on stimulation of pentose phosphate cycle activity by H2O2 did not appear to be due to the inhibitor itself, but rather to the overall level of glutathione. Glutathione could have a role in maintaining activity of the pentose phosphate cycle at a level which is appropriate for the severity of the oxidative challenge as well as for the capacity of the cellular antioxidant defenses.

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D008717	Methionine Sulfoximine		Sulfoximine, Methionine
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
D010269	Paraquat	A poisonous dipyridilium compound used as contact herbicide. Contact with concentrated solutions causes irritation of the skin, cracking and shedding of the nails, and delayed healing of cuts and wounds.	Methyl Viologen,Gramoxone,Paragreen A,Viologen, Methyl
D010427	Pentose Phosphate Pathway	An oxidative decarboxylation process that converts GLUCOSE-6-PHOSPHATE to D-ribose-5-phosphate via 6-phosphogluconate. The pentose product is used in the biosynthesis of NUCLEIC ACIDS. The generated energy is stored in the form of NADPH. This pathway is prominent in tissues which are active in the synthesis of FATTY ACIDS and STEROIDS.	Hexose Monophosphate Shunt,Pentose Phosphate Shunt,Pentose Shunt,Pentosephosphate Pathway,Pentose-Phosphate Pathway,Pentosephosphate Shunt,Hexose Monophosphate Shunts,Pathway, Pentose Phosphate,Pathway, Pentose-Phosphate,Pathway, Pentosephosphate,Pathways, Pentose Phosphate,Pathways, Pentose-Phosphate,Pathways, Pentosephosphate,Pentose Phosphate Pathways,Pentose Phosphate Shunts,Pentose Shunts,Pentose-Phosphate Pathways,Pentosephosphate Pathways,Pentosephosphate Shunts,Shunt, Hexose Monophosphate,Shunt, Pentose,Shunt, Pentose Phosphate,Shunt, Pentosephosphate,Shunts, Hexose Monophosphate,Shunts, Pentose,Shunts, Pentose Phosphate,Shunts, Pentosephosphate
D002330	Carmustine	A cell-cycle phase nonspecific alkylating antineoplastic agent. It is used in the treatment of brain tumors and various other malignant neoplasms. (From Martindale, The Extra Pharmacopoeia, 30th ed, p462) This substance may reasonably be anticipated to be a carcinogen according to the Fourth Annual Report on Carcinogens (NTP 85-002, 1985). (From Merck Index, 11th ed)	BCNU,1,3-Bis(2-Chloroethyl)-1-Nitrosourea,BiCNU,FIVB,N,N'-Bis(2-Chloroethyl)-N-Nitrosourea,Nitrumon
D004791	Enzyme Inhibitors	Compounds or agents that combine with an enzyme in such a manner as to prevent the normal substrate-enzyme combination and the catalytic reaction.	Enzyme Inhibitor,Inhibitor, Enzyme,Inhibitors, Enzyme
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
D005954	Glucosephosphate Dehydrogenase		Glucose-6-Phosphate Dehydrogenase,Dehydrogenase, Glucose-6-Phosphate,Dehydrogenase, Glucosephosphate,Glucose 6 Phosphate Dehydrogenase
D005978	Glutathione	A tripeptide with many roles in cells. It conjugates to drugs to make them more soluble for excretion, is a cofactor for some enzymes, is involved in protein disulfide bond rearrangement and reduces peroxides.	Reduced Glutathione,gamma-L-Glu-L-Cys-Gly,gamma-L-Glutamyl-L-Cysteinylglycine,Glutathione, Reduced,gamma L Glu L Cys Gly,gamma L Glutamyl L Cysteinylglycine