Detail of "643-13-0"

Reference

Gluconeogenesis in rabbit liver

Gluconeogenesis in rabbit liver. II. Gluconeogenesis and its enhancement by glucagon, epinephrine and cyclic AMP. Huibregtse, Charles A.; Rufo, Gerald A., Jr.; Ray, Paul D. (Dep. Biochem., Univ. North Dakota Sch. Med., Grand Forks, N. Dak., USA). Biochim. Biophys. Acta, 499(1), 99-110 (English) 1977. CODEN: BBACAQ. DOCUMENT TYPE: Journal CA Section: 2 (Hormone Pharmacology) Gluconeogenesis from various substrates was demonstrated in isolated rabbit liver. Rates of gluconeogenesis (in .mu.mol/min/g liver) for various substrates were as follows: D-fructose [57-48-7], 0.95; dihydroxyacetone [96-26-4], 0.60; L-lactate [79-33-4], 0.52; and glycerol [56-81-5], 0.34. Gluconeogenesis from L-lactate and dihydroxyacetone was stimulated .apprx.1.7-1.8 fold by 10-8M glucagon [9007-92-5], 10-6M epinephrine [51-43-4], and 10-4M cyclic AMP (I) [60-92-4]. Gluconeogenesis from D-fructose was stimulated only 1.3-fold by I. Plots of hepatic metabolite concns., before and after addn. of effectors to livers given L-lactate or dihydroxyacetone, showed highly significant increases in the concns. of fluctose 6-phosphate [643-13-0] and glucose 6-phosphate [56-73-5] after addn. of effectors. Apparently glucagon, epinephrine, and I exert a major pos. influence on the interconversion of fructose 1,6-diphosphate and fructose 6-phosphate; conversely, these effectors did not appear to influence the conversion of L-lactate to phosphoenolpyruvate. Quinolinic acid was ineffective as an inhibitor of gluconeogenesis from L-lactate in fasted rabbit livers; aminooxyacetate at various concns. inhibited gluconeogenesis from L-lactate by 50-70%, suggesting that cytosolic phosphoenolpyruvate carboxykinase compared to the mitochondrial carboxykinase is of at least equal importance for synthesis of phosphoenolpyruvate enroute to glucose.

Effect of ring substituents on the transketolase-catalyzed conversion of nitroso aromatics to hydroxamic acids

Effect of ring substituents on the transketolase-catalyzed conversion of nitroso aromatics to hydroxamic acids. Corbett, Michael D.; Corbett, Bernadette R. (Dep. Food Sci. Hum. Nutr., Univ. Florida, Gainesville, FL 32611, USA). Biochem. Pharmacol., 35(20), 3613-21 (English) 1986.Several reagents such as 9014-48-6 is used here. CODEN: BCPCA6. ISSN: 0006-2952. DOCUMENT TYPE: Journal CA Section: 4 (Toxicology) Transketolase [9014-48-6] catalyzed the conversion of 8 different arom. C-nitroso compds. into the corresponding N-glycolyl-derived hydroxamic acids. Three of the nitroso compds. were also converted in part to the arylhydroxylamines by a reductive process. A correlation was found for the rates of prodn. of these metabolites with the electronegativities of substituent groups that were present on the arom. ring. The rates of reaction of these substituted nitroso substrates with transketolase and D-fructose 6-phosphate [643-13-0] decreased in the order 4-NO2 >> 4-CF3 > 3-CF3, unsubstituted > 4-Cl > 4-CH3, 4-Ph > 4-OC2H5. N,N-Dimethyl-p-nitrosoaniline (I) [138-89-6] was not metabolized by transketolase under the conditions employed for the other substrates. Those substrates possessing the strong electron-withdrawing groups 4-NO2, 4-CF3, and 3-CF3 were the only substrates that underwent enzymic redn. to the hydroxylamines as a competing process. A mechanism was proposed that involves a redox reaction between the nitroso substrate and the enzymic intermediate active glycolaldehyde at the active site of transketolase. .