Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.1.1.49 (glucose-6-phosphate dehydrogenase)
 7,794 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

When 1-, 2- and 9-month-old rats previously adapted to a commercial stock diet were fed a fat-free diet (induction) and also when the process was reversed (repression), the turnovers of lipogenic enzymes in liver were measured by following time courses for the change of the enzyme activities. The magnitudes of the induction of glucose-6-phosphate dehydrogenase, malic enzyme and acetyl-CoA carboxylase were very high in 1-month-old rats and then decreased with aging. In the induction phase, the rates of synthesis of the enzymes were markedly decreased with increasing age as compared with the rate constants of degradation. The age-dependent alterations were not shown so much in the repression phase as in the induction phase. It is suggested that the age-dependent impairment in induction may be due to some alterations in the enzyme-forming system.
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PMID:Age-dependent modifications of lipogenic enzymes. 611 23

During the formation of two layers of adipose tissue in the pig's body, starting from the 80th day after birth, samples were obtained by biopsy and analyzed for gross constituents and enzymes concerned with fatty-acid biosynthesis. These two layers differ in total lipid and water content and demonstrate more subtle differences amongst DNA, protein, collagen and sodium concentrations when comparisons are made in regard to age, sex, and breeding selection for low-fat animals. Acetyl-CoA carboxylase, malic enzyme and glucose-6-phosphate dehydrogenase are more active in the inner layer, while 6-phosphogluconate and isocitrate dehydrogenases are distinguishable in the two layers of adipose tissue as well if age, sex, and breeding line are taken into consideration. The data form the basis for a more detailed study of lipogenic potentials in adipose tissue (next paper).
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PMID:Biochemical characterization of the layers of subcutaneous adipose tissue in the pig body. 612 11

The responses of rat hepatic and brown adipose tissue in vivo lipogenesis to premature (15 days) and normal (21 days) weaning have been correlated to changes in the activities of acetyl-CoA carboxylase and two NADPH-producing enzymes, malic enzyme and glucose-6-phosphate dehydrogenase. Both tissues show an induction of lipogenesis in response to weaning. In the liver, lipogenic flux is closely linked to the activity of acetyl-CoA carboxylase, but not necessarily that of malic enzyme or glucose-6-phosphate dehydrogenase, whereas no such dissociation between enzyme activity and flux rate occurs in brown adipose tissue. Thyroid hormones, implicated in many physiological changes around weaning, do not seem to play a primary role in the adaptation of lipogenesis to the dietary change at this time, although a permissive role in both tissues is possible.
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PMID:Lipogenesis at the suckling-weaning transition in liver and brown adipose tissue of the rat. 612 98

The hormonal regulation of two regulatory enzymes of fatty acid synthesis acetyl-CoA carboxylase (EC 6.4.1.2) and glucose-6-phosphate dehydrogenase (EC 1.1.1.49), has been investigated in human diploid fibroblasts. There was a 35% increase in acetyl-CoA carboxylase activity, 72 h following addition of 10 microU/ml insulin to the culture medium. Addition of 1 microgram/ml of 3,3'5-triiodothyronine for 72 h resulted in an increase in acetyl-CoA carboxylase activity to 166% of the controls. The simultaneous addition of 1 microgram/ml triiodothyronine and 10 mU/ml insulin caused the enzyme activity to rise to 240% of the controls. A dose-dependent reduction in acetyl-CoA carboxylase activity was brought about by 1 X 10(-4) to 1 X 10(-3) M dibutyryl cyclic AMP. The earliest effect of dibutyryl cyclic AMP was observed within 24 h. Glucose-6-phosphate dehydrogenase followed qualitatively the same pattern of response, whereas the constitutive enzyme, lactate dehydrogenase (EC 1.1.1.27), did not show significant changes in these experiments. The data demonstrate common features of hormonal regulation of lipogenesis in human fibroblasts with liver and adipose tissue and substantiate the growing evidence that thyroid hormones are of major importance for the regulation of this process.
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PMID:Regulation of lipogenic enzymes in human diploid fibroblasts by hormones. 613 Jul 94

The effects of aging on enzyme qualities of glucose-6-phosphate dehydrogenase, malic enzyme and acetyl-CoA carboxylase were investigated. The Ouchterlony double-diffusion pattern showed that the enzymes from livers of rats of different ages are immunologically similar to each other. In addition, immunochemical titration demonstrated that the changes in the levels of activity of rats of different age are accompanied by proportionate changes in the quantity of the enzyme protein. The Kms of the enzymes for substrates were not altered by aging. It is suggested that the age-dependent impairments of the enzyme induction (Iritani, N., Fukuda, H., and Fukuda, E. (1981) Biochim. Biophys. Acta, 665, 639) can be ascribed to decreases in the rise of enzyme protein quantities.
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PMID:Immunological studies of lipogenic enzymes during aging. 613 Nov 14

When rats adapted to a stock diet were fed on various high-carbohydrate diets, the hepatic activities of glucose-6-phosphate dehydrogenase, malic enzyme and acetyl-CoA carboxylase were more greatly increased by fructose than by any other carbohydrate. Even in the diabetic state, the enzyme activities were somewhat increased by fructose feeding. After feeding on the diets for 9 days, the hepatic concentrations of intermediates of carbohydrate metabolism were generally lower in the diabetics than in the normals. Moreover, in both the normal and diabetic rats, the concentrations of fructose-1-phosphate, acetyl-CoA, citrate and malate were increased by fructose as were the enzyme activities. These results suggest that the metabolic pathway of fructose is predominant with respect to that of glucose and consequently lipogenesis may be able to be increased in the fructose-fed rats.
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PMID:Effects of high-fructose diet on lipogenic enzymes and their substrate and effector levels in diabetic rats. 614 42

The extent of fatty acid synthesis from [1-14C]acetate in liver slices was reduced 6-fold when eels were fasted for 1-7 weeks and 20-fold when fasted for 39 weeks; thereafter hepatic lipogenesis seemed to remain constant for up to 95 weeks of fasting. After a 1-3 week fast some hepatic enzyme activities were reduced (acetyl-CoA carboxylase decreased 2-fold and fatty acid synthetase declined 5-fold), while others remained unchanged (glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, alpha-glycerol phosphate dehydrogenase as well as malic enzyme and ATP-citrate lyase). The optimum temperature for measuring both total lipid synthesis and lipogenic enzyme activity in eel liver was found to be 30 degrees C.
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PMID:The effect of prolonged fasting on total lipid synthesis and enzyme activities in the liver of the European eel (Anguilla anguilla). 615 Aug 5

The liver lipogenic enzymes are compared among rats, chickens, frogs and fish. Although the apparent Km values of glucose-6-phosphate dehydrogenase for glucose-6-phosphate are not much different among all the species, those of malic enzyme for malate are much higher in chickens and fish than in rats and frogs. Glucose-6-phosphate dehydrogenase showed very high activities compared with malic enzyme in fish liver, and malic enzyme showed high activities in chicken liver. Although the apparent Km values of acetyl-CoA carboxylase and fatty acid synthetase for substrates are in the same range among all the animals, the activity of acetyl-CoA carboxylase seems to be extremely low in fish and frog livers, and that of fatty acid synthetase is low in frog livers only. In addition, the apparent Km values of alpha-glycerophosphate acyltransferase of fish liver are very high, and the enzyme activity appears to be extremely low compared to the others. Therefore, the enzymes at the first steps of both fatty acid and glycerolipid syntheses of poikilothermos animals appear to be very low. On the other hand, the Ouchterlony double-diffusion patterns showed that the lipogenic enzymes of chickens, frogs and fish are immunologically different from those of rats, with the exception of acetyl-CoA carboxylase in chickens. Therefore, it is suggested that the fatty acid and glycerolipid forming systems of poikilothermos animals are quite different from those of homoiothermos and the lipogenesis is very low in poikilothermos.
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PMID:Comparative study of lipogenic enzymes in several vertebrates. 615 20

Using primary cultures of adult rat hepatocytes, the regulation of the following lipogenic enzymes was studied: glucose-6-phosphate dehydrogenase, malic enzyme, ATP-citrate lyase, acetyl-CoA carboxylase, fatty acid synthetase, and stearoyl-CoA desaturase. The addition to the culture medium of either insulin or triiodothyronine produced a 2-3-fold increase in each of the individual enzyme activities whereas glucagon slightly decreased enzyme activities. The addition to the medium of 8-bromoguanosine 3,'5'-monophosphate had no effect on any of the enzyme activities unless glucose was also added to the culture medium. Glucose addition alone to the culture medium was without any effect; however, glucose enhanced the stimulation of enzyme activity due to insulin. The addition of fructose or glycerol, even in the absence of insulin, increased the activities of each of the enzymes studied 2-3-fold. The increases in enzyme activity brought about by insulin or fructose were apparently the result of de novo enzyme synthesis, as indicated by the observation that the increases were not noted in the presence of cordycepin or cycloheximide. Immunoprecipitation of ATP-citrate lyase from hepatocytes pulse-labeled with [3H]leucine indicated that the induction of this enzyme in response to the addition of fructose or glycerol to the culture medium was the result of an increase in the rate of synthesis of the enzyme. These results indicate that the activity and synthesis of individual enzymes involved in lipogenesis are increased in response to the metabolism of carbohydrate independently in part from hormonal effects.
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PMID:Induction of lipogenic enzymes in primary cultures of rat hepatocytes. Relationship between lipogenesis and carbohydrate metabolism. 629 23

Measurements have been made of the activity of the enzymes of the glycolytic, pentose phosphate and lipogenic pathways and of some marker enzymes of the tricarboxylic acid cycle in brains of rats aged between 20 days and 24 months. In general, the activity of the most enzymes measured was unchanged by aging but exceptions to this were increases of hexokinase, glucose-6-phosphate dehydrogenase and 'malic enzyme' and decreases of ATP-citrate lyase, acetyl-CoA carboxylase and fatty acid synthetase. An exceptionally large (2-fold) increase in the activity of cytosolic glycerol 3-phosphate dehydrogenase was noted. These changes are considered in relation to the overall metabolic activity of the brain.
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PMID:Age-related changes in enzymes of rat brain. 1. Enzymes of glycolysis, the pentose phosphate pathway and lipogenesis. 723 73


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