UDPG-glycogen Transglucosylase Research Articles

Commentary on ‘Insulin-mediated effect on the activity of UDPG-glycogen transglucosylase of muscle’ by C. Villar-Palasí and J. Larner Biochim. Biophys. Acta 39 (1960) 171–173

Commentary on ‘Insulin-mediated effect on the activity of UDPG-glycogen transglucosylase of muscle’ by C. Villar-Palasí and J. Larner Biochim. Biophys. Acta 39 (1960) 171–173

UDP as the inhibitor of glycogen synthesis from crustacean eyestalks

The inhibitor of UDPG-glycogen transglucosylase reported earlier to occur in crustacean eyestalks is shown to be uridine-diphosphate (UDP). UDP is shown to be secreted internally, and to participate in the regulation of carbohydrate metabolism in crustaceans.

A histochemical study of liver enzymes involved in glycogen metabolism in the x-irradiated rat.

The liver enzymes responsible for the breakdown and synthesis of glycogen from glucose have been investigated cytochemically in rats exposed to 1200 rads of x-irradiation. It was found that significant changes occur in their activities and that amylophosphorylase and amylo-1,6-glucosidase (debranching enzyme), both of which are responsible for the conversion of glycogen to glucose, are markedly inhibited by radiation. A significant inhibition of the activity of 1,4→1,6 transglucosidase (branching enzyme) was also observed. In contrast, the activity of UDPG-glycogen transglucosylase, which is responsible for the in vivo synthesis of 1,4-polysaccharides, was found to be stimulated.

Endocrine control of glycogen synthesis in crabs

1. 1. Eyestalk removal in crabs Hemigrapsus nudus and Cancer magister (intermolt stage) is followed by an increase in the activity of UDPG-Glycogen transglucosylase system (UDPG-GT) in muscle tissue. 2. 2. Injection of eyestalk extract into eyestalkless animals decreases the enzyme activity nearly to normal levels. 3. 3. Net synthesis of glycogen in muscle and hepatopancreas, from either glucose or maltose, is not increased by eyestalk removal or depressed by the eyestalk extract injection. 4. 4. The turnover of glucose in glycogen in muscle and hepatopancreas is increased, as indicated by increased specific activity of the glycogen following injection of C 14 glucose or C 14 maltose, by eyestalk removal. 5. 5. Eyestalk extracts have been fractionated by chromatography on Sephadex and the inhibitory factor localized in a definite fraction. 6. 6. The increased turnover is treturned to normal by the injection of crude eyestalk extract or of the purified fraction containing the transglucosylase inhibitor. 7. 7. Eyestalk removal is followed by a marked decrease in total phosphorylase and an increase in the percentage of “inactive” phosphorylase “ b”, but these changes are not reversed by injection of purified fraction of eyestalk extracts. 8. 8. The purified fraction does not increase blood glucose when injected, but does increase the maltose concentration in the blood. 9. 9. These results support the hypothesis that the inhibitor of UDPG-GT acts as a hormone in the control of glycogen synthesis and suggests the possibility that other factors may also be involved in the control of carbohydrate metabolism.

METABOLIC INFLUENCES ON ENZYMES OF GLYCOGEN SYNTHESIS AND BREAKDOWN IN ADIPOSE TISSUE.

Rat adipose tissue from different body sites was shown to contain uridine diphosphoglucose (UDPG)-transglucosylase activity, which on the basis of protein content was comparable to or higher than that reported for muscle or liver. In epididymal adipose tissue, the activity of UDPG-glycogen transglucosylase and phosphorylase, as well as the content of glycogen per wet weight, decreased with increasing age of the animals in parallel with the decrease of tissue protein content. On prolonged fast the activity of UDPG-glycogen transglucosylase and phosphorylase per milligram protein dropped by 25–50% of the control value. On refeeding, the extent of changes was variable but, in general, at 24 hr control or higher levels of activity were reached and at 48 hr the activities were elevated. The ratio of glucose 6-phosphate independent activity of UDPG-glycogen transglucosylase to total activity was not affected by fasting and refeeding or by the administration of glucose with insulin. In adrenalectomized rats, with high adipose tissue glycogen, no change in UDPG-glycogen transglucosylase was found, whereas the levels of phosphorylase were elevated. Epinephrine in vivo and in vitro did not affect the activity of UDPG-glycogen transglucosylase of adipose tissue.

Glycogen deposition in adipose tissue: Variations in levels of glycogen-cycle enzymes during fasting and refeeding

The influence of fasting and fasting-refeeding upon the activities of the glycogen-cycle enzymes in rat epididymal adipose tissue has been investigated. In fed (control) animals UDPG-glycogen transglucosylase is the limiting enzyme in the pathway between glucose and glycogen in adipose tissue. Fasting for 48 hours significantly lowered the levels of all of the enzymes of the glycogen cycle, and refeeding of a low-fat, high-carbohydrate diet for either 24 or 48 hours following a 48-hour fast resulted in an apparent sequential return of the enzyme activities in the order in which they appear in the glucose to glycogen pathway. Endogenous glucose-6-phosphate levels in adipose tissue during the various nutritional states were not significantly different from the fed state, and thus the activation of UDPG-glycogen transglucosylase by glucose-6-phosphate apparently does not account for the marked deposition of glycogen which occurs during refeeding.

SOME BIOCHEMICAL CHANGES IN THE GUINEA PIG DURING INFECTION WITH COXIELLA BURNETII.

Paretsky, D. (University of Kansas, Lawrence), C. M. Downs, and C. W. Salmon. Some biochemical changes in the guinea pig during infection with Coxiella burnetii. J. Bacteriol. 88:137-142. 1964.-Guinea pigs infected with Coxiella burnetii, the rickettsial agent of Q fever, were studied for 11 days postinfection. Maximal changes in liver lipids, liver phosphorylase, and uridine diphosphate glucose (UDPG)-glycogen glucosyl-transferase activities occurred 3 to 4 days post-infection. In this period, total liver lipids increased from 1.26 to 5.46 mg/mg of N, with the largest increment in the glyceride fraction. Liver glycogen virtually disappeared by the second day, with no chemically detectable restoration until the eleventh day. A pattern of altered phosphorylase and UDPG-glycogen transglucosylase activities was observed, with maximal phosphorylase and minimal glucosyltransferase activities at the third and fourth days. Histochemical observations confirmed chemical analyses for lipids and glycogen.

GLYCOGEN SYNTHESIS IN THE INSECT FAT BODY.

A tissue extract prepared from the fat body of the american cockroach (Periplaneta americana L.) has been shown to contain UDPG-pyrophosphorylase (EC 2.7.7.9) and UDPG-glycogen transglucosylase (EC 2.4.i.ii) activity. The latter enzyme is not stimulated by Glc-6-P. Addition of Glci-P to the system results in a substantial enhancement of [14C]glucose incorporation from UDPG. The present evidence suggests that Glc-i-P is a true activator of UDPG-glycogen transglucosylase of the cockroach fat body.

Glycogen synthesis in the insect fat body

A tissue extract prepared from the fat body of the american cockroach (Periplaneta americana L.) has been shown to contain UDPG-pyrophosphorylase (EC 2.7.7.9) and UDPG-glycogen transglucosylase (EC 2.4.i.ii) activity. The latter enzyme is not stimulated by Glc-6-P. Addition of Glci-P to the system results in a substantial enhancement of [14C]glucose incorporation from UDPG. The present evidence suggests that Glc-i-P is a true activator of UDPG-glycogen transglucosylase of the cockroach fat body.

UDPG-glycogen transglucosylase and a natural inhibitor in crustacean tissues

1. 1. UDPG-glycogen transglycosylase has been demonstrated in the major tissues of a crab ( Cancer magister) and in the muscles of crabs ( C. magister, Hemigrapsus nudus), a crayfish ( Astacus cambarus), molluskus ( Mytilus californianus Tegula funebralis), fishes ( Pomoxis annularis, Salmo gairdneri, Aequidens portalegrensis) and amphibians ( Rana pipiens, Bufo marinus). 2. 2. The crab muscle enzyme requires glucose-6-phosphate (glc-6-p) and has a pH optimum at 8·3. It is unstable in crude preparations, but is stabilized by addition of fluoride and glc-6-p. 3. 3. The enzyme activity is not associated with any specific sedimentable fraction in homogenates. 4. 4. Mixtures of homogenates of muscle with homogenates of hepatopancreas or eyestalk have an enzyme activity lower than predicted from the activities of homogenates assayed separately. The inhibitory effect of hepatopancreas homogenates is attributed to presence of hydrolytic enzymes, but the inhibitory effect of eyestalk extracts is attributed to a specific inhibitory factor. 5. 5. The inhibitory factor in eyestalk extracts is non-dialyzable; it is partly but not wholly destroyed by boiling, or treatment with 95 per cent alcohol or 1 N HNl in the cold. The factor is not soluble in ether. 6. 6. The inhibitory effect of eyestalk extracts varies with the stage of the donor in the intermolt cycle. 7. 7. Eyestalk extracts of crabs inhibit transglucosylase activity in muscle extracts from crabs, crayfis, mollusks and vertebrates. 8. 8. The possible relation of the inhibitory factor to the diabetogenic hormone of crustaceans, and to the control of carbohydrate metabolism, is discussed.

Study of glycogen synthesizing and degrading enzymes of guinea pig liver in experimental tuberculosis

Enzymes of the glycogen cycle, namely, UDPG-glycogen transglucosylase, phosphorylase, phosphoglucomutase, and glucose-6-phosphatase, were assayed in the liver of normal and tuberculous guinea pigs. A significant decrease in the activities of the first three enzymes and increase in that of the last one were noted. The decrease in the activity of UDPG-glycogen transglucosylase was of significant magnitude to account for the depletion of the hepatic glycogen in tuberculous guinea pigs.

Studies on UDPG-Glycogen Transglucosylase. I. Preparation and Differentiation of Two Activities of UDPG-Glycogen Transglucosylase from Rat Skeletal Muscle*

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTStudies on UDPG-Glycogen Transglucosylase. I. Preparation and Differentiation of Two Activities of UDPG-Glycogen Transglucosylase from Rat Skeletal Muscle*M. Rosell-Perez, C. Villar-Palasi, and Joseph LarnerCite this: Biochemistry 1962, 1, 5, 763–768Publication Date (Print):September 1, 1962Publication History Published online1 May 2002Published inissue 1 September 1962https://doi.org/10.1021/bi00911a005RIGHTS & PERMISSIONSArticle Views51Altmetric-Citations133LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (608 KB) Get e-Alerts Get e-Alerts

Selective response of liver enzymes to the administration of different diets after fasting

The activities of glucokinase, UDPG-glycogen transglucosylase, glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase, referred to 100 g. of body weight, decreased in the liver of animals fed with a high-fat diet for 6 days and were maintained at normal levels in rats fed a high-carbohydrate, fat-free diet. The enzymes decreased after a 48-hr, fasting period and returned to normal values after subsequent feeding with an equilibrated diet. The administration of a high-fat diet did not induce recovery of enzyme activities; only 6-phosphogluconato dehydrogenase recovered partially. In contrast, following administration of a diet consisting solely of carbohydrates, glucokinase recovered to normal levels within 1 day, while glucose 6-phosphate and 6-phosphogluconate dehydrogenases remained at the same low levels observed in fasted animals. The technique of feeding, following a fasting period, is considered a good tool for the study of the dependence of enzyme activities on the nature of the diet.

Effect of eyestalk extract on UDPG-glycogen transglucosylase in crab muscle

Effect of eyestalk extract on UDPG-glycogen transglucosylase in crab muscle

Insulin treatment and increased UDPG-glycogen transglucosylase activity in muscle

Phosphoglucomutase, UDP-glucose pyrophosphorylase, phosphorylase, and UDP-glucose glycogen transglucosylase activities were compared in extracts prepared from diaphragms incubated without and with insulin. No differences in the activities of the first three enzymes were found, but UDP-glucose glycogen transglucosylase activity was found to be increased in extracts of diaphragms incubated with insulin when assayed without addition of glucose-6-P. When glucose-6-P was added in the assay, the activities of extracts prepared from control and insulin-treated diaphragms were both increased and were the same. The increase in enzyme activity by insulin was not duplicated by incubation of diaphragms in an increased concentration of glucose. Further, it was not obtained after incubation of diaphragms with insulin at 0 °C. Enzyme activity was increased, however, after incubation of diaphragms with insulin without glucose in the incubation medium. The increased enzyme activity was retained after dialysis or ammonium sulfate precipitation. The increase in transglucosylase activity is in keeping with increased glycogen content after insulin treatment and supports the role of UDP-glucose glycogen transglucosylase in glycogen 1,4-bond synthesis. An explanation of the partial increase of enzyme activity after insulin treatment based on the presence of two activity forms of the enzyme is presented. These studies demonstrate a new mode of hormonal control of glycogen metabolism.

Dissociation of Uridine Diphosphate Glucose-Glycogen Transglucosylase from Phosphorylase Activity in Individual Muscle Fibers

SummaryA reciprocal relationship between phosphorylase and UDPG-glycogen transglucosylase activity has been demonstrated by a histochemical technic in individual fibers of resting rat skeletal muscle. In general, polysaccharide formed from glucose-1-phosphate was deposited in the large (white) type of fiber and that from UDPG in the small (red) fibers.

Insulin-mediated effect on the activity of UDPG-glycogen transglucosylase of muscle

Insulin-mediated effect on the activity of UDPG-glycogen transglucosylase of muscle