Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.3.9 (glucose-6-phosphatase)
 3,081 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The retinal glucose-6-phosphatase system was studied in rabbits. Following subcellular fractionation of the retina by differential centrifugation, the microsomal fraction was used for spectrophotometrical assay of the phosphate release. Assays were performed with intact and Triton X-100-treated preparations. Intactness of the microsomal preparations was assessed by using 2 mM mannose-6-phosphate as a substrate. Latencies towards glucose-6-phosphate and mannose-6-phosphate were 13.1 +/- 4.1% (n = 5) and 92.5 +/- 2.8% (n = 5) respectively; the difference between them was significant (P < 0.001). Pyridoxal-5'-phosphate specifically inhibited the retinal glucose-6-phosphate translocase activity at concentrations of 5-10 mM. Postnatal development was studied at postnatal days 1, 10, 17, 25, 36, 46, 54 and 70. At the postnatal 17th day, the retinal glucose-6-phosphatase specific activity was 60.1 +/- 3.8 (n = 3) nmol/min/mg protein which was one-third of the adult level [173.6 +/- 26.2 (n = 6) nmol/min/mg protein] (P < 0.001). This finding suggested that, in the rabbit, development of this enzyme system might coincide with development of retinal glucose catabolism.
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PMID:The glucose-6-phosphatase system in the retina. 133 21

In 19 patients with a deficiency of glucose-6-phosphatase and 1 patient with a deficiency of glucose-6-phosphate translocase, the effect of nocturnal gastric drip feeding (GDF) on growth and plasma lipids and apolipoproteins was studied. The effect on growth was estimated by determining the height standard deviation score (SDS) of the patients and comparing its changes (delta SDS) over 4-, 2-, and 1-y periods before and 1-, 2-, 5-, and 8-y periods after the institution of GDF. The effect of GDF on plasma lipids and apolipoproteins was investigated by following the concentrations of triglycerides, cholesterol, and apolipoproteins A-I, A-II, B, C-I, C-II, C-III, and E. Growth caught up significantly or remained in the normal range in 14 patients. They were defined as responders to GDF. In the other six patients, growth caught up insufficiently or showed a further deceleration. They were defined as nonresponders to GDF. GDF had only a temporary and marginal effect on plasma lipids and apolipoproteins, but after 5-8 y, the levels of plasma triglycerides, cholesterol, apolipoprotein, B, C-I, C-II, C-III, and E increased further in both responders and nonresponders, whereas apolipoproteins A-I and A-II decreased in nonresponders. There were minor differences in the levels of lipids and apolipoproteins between responders and nonresponders without any discernible trends during the first years of GDF.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Gastric drip feeding in patients with glycogen storage disease type I: its effects on growth and plasma lipids and apolipoproteins. 254 71

1. Type 1b and type 1c glycogen-storage disease are caused respectively by deficiencies of the glucose-6-phosphate translocase and the phosphate/pyrophosphate translocase of the human hepatic microsomal glucose-6-phosphatase system. 2. Current methods of unequivocally diagnosing type 1b and type 1c glycogen storage disease are indirect and complex. 3. We have therefore developed a simple, rapid and direct microfiltration assay for the glucose-6-phosphate translocase and the phosphate/pyrophosphate translocase. 4. We have demonstrated that the microfiltration assay can be used to directly diagnose type 1b and 1c glycogen-storage disease in microsomes isolated from hepatic needle-biopsy samples.
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PMID:A direct method for the diagnosis of human hepatic type 1b and type 1c glycogen-storage disease. 254 42

A membrane filter procedure developed by Igarashi et al. (1984) for the measurement of glucose 6-phosphate uptake by the microsomes has been demonstrated to be a good method for assaying glucose-6-phosphate translocase, an obligatory component of the microsomal glucose-6-phosphatase system. When glucose-6-phosphate translocase was assayed in developing and diabetic rat livers independently of hexose-6-phosphate phosphohydrolase, another obligatory component of the glucose-6-phosphatase system, the two activities were found to undergo alterations, whose profiles, however, were quite distinct from each other. The profile of the microsomal glucose-6-phosphatase activity resembles the profile of the phosphohydrolase activity rather than that of the translocase activity, suggesting that the phosphohydrolase may be rate-limiting at least under these conditions. AH-109A, a strain of transplantable rat ascites hepatoma, was found to lack both glucose-6-phosphate translocase and hexose-6-phosphate phosphohydrolase activities.
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PMID:Analysis of glucose-6-phosphate translocase and hexose-6-phosphate phosphohydrolase, the two obligatory components of microsomal glucose-6-phosphatase system, in rat liver. 285 Jun 43

The activities of glucose-6-phosphate hydrolase and glucose-6-phosphate translocase were determined in rats fasted for 1-3 days and in animals fasted for one day and then either refed with mixed pellet or given oral or intraperitoneal glucose. The assay was based on the colorimetric measurement of the released inorganic phosphate. Fasting over 24 h significantly increased both the translocase and the hydrolase activity of glucose-6-phosphatase. These parameters showed a further increase when rats were fasted for another 24 h. In animals fasted for 24 h and then refed with standardized pellet diet, a progressive fall of enzyme activity was noticed. However, even 72 h of refeeding did not lead to complete normalization. Glucose given orally or intraperitoneally also suppressed the enzyme activity, although the effect was somewhat delayed. As expected, in fasting rats glucose and insulin levels were significantly decreased. Normoglycaemia was established after just 24 h, regardless of refeeding with pellets or with glucose. The former group exhibited hyper- and the latter hypo-insulinaemic pattern. We speculate that augmented activity of hepatic glucose-6-phosphatase during fasting stimulates the metabolism of glucose through the glucose cycle and is thereby at least partially responsible for insulin resistance accompanying the fasting state.
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PMID:Effects of fasting and refeeding on the activity of hepatic glucose-6-phosphatase in rats. 299 2

The effect of 1-cyclohexyl-3-(2-morpholinoethyl)carbodiimide (CMC) on the reactions catalyzed by the glucose-6-phosphatase system of rat liver microsomes was studied. Modification of the intact microsomes by CMC leads to the inhibition of the glucose-6-phosphatase, pyrophosphate:glucose and carbamoyl-phosphate : glucose phosphotransferase activities of the system. The activities are restored by the disruption of the microsomal permeability barrier. The mannose-6-phosphate, pyrophosphate, and carbamoyl-phosphate phosphohydrolase activities of the intact as well as the disrupted microsomes were not affected by CMC. It follows from the results obtained that CMC inactivates the microsomal glucose-6-phosphate translocase, the inactivation is a result of the modification of a single sulfhydryl or amino group of the translocase; pyrophosphate, carbamoyl phosphate and inorganic phosphate are transported across the microsomal membrane without participation of the glucose-6-phosphate translocase; pyrophosphate and carbamoyl phosphate may act as the phosphate donors in the glucose phosphorylation reactions in vivo.
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PMID:The effect of 1-cyclohexyl-3-(2-morpholinoethyl)carbodiimide on the rat liver microsomal glucose-6-phosphatase system. 302 57

A workshop was held on "Aspects of treatment of patients with glycogen storage disease" within the framework of the Concerted Action "Inborn errors of metabolism" of the European Communities. Consensus was reached on the main issues of treatment of patients with deficiency of glucose-6-phosphatase, glucose-6-phosphate translocase, debranching enzyme, liver phosphorylase and phosphorylase-b-kinase. The resulting recommendations are reported.
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PMID:Glycogen storage disease: recommendations for treatment. 329 44

Growth retardation and lactic aciduria are well-known abnormalities in patients with a deficiency of either glucose-6-phosphatase or glucose-6-phosphate translocase. In 19 patients with glucose-6-phosphatase and two patients with glucose-6-phosphate translocase, growth retardation was quantified by calculating the height standard deviation score. The urinary excretion of lactate and some other metabolites was quantified by calculating the lactate/creatinine, 2-oxoglutarate/creatinine, citrate/creatinine, and glycerol/creatinine ratios in urine. Significant correlations were found between the lactate/creatinine ratio, the 2-oxoglutarate/creatinine ratio, and height SD score. Urinary lactate appeared to respond promptly to changes of the diet, while urinary 2-oxoglutarate responded only slowly, as did growth itself. The citrate/creatinine ratio and the glycerol/creatinine ratio were within the normal range and varied little. It was concluded that the urinary 2-oxoglutarate excretion primarily reflects the severity of the disease as expressed in stunted growth. Thus, while urinary lactate levels are more suitable for monitoring the diet, urinary 2-oxoglutarate levels can be used as an indication for intensive treatment with hyperalimentation.
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PMID:Urinary excretion of lactate, 2-oxoglutarate, citrate, and glycerol in patients with glycogenosis type I. 347 Jul 5

We have examined the interactions of the histidine-specific reagent diethyl pyrocarbonate (DEPC) with the components of the rat hepatic glucose-6-phosphatase system (EC 3.1.3.9). DEPC is the first known reagent that satisfies the criteria of an active-site-specific label for the phosphohydrolase component. (a) It inactivates through formation of a stable covalent bond. (b) It is effective at reasonably low concentrations (2-4 mM) under relatively mild conditions (e.g. 30 degrees C at neutral pH). (c) Inactivation is substantially blocked by glucose 6-phosphate, Pi and NaF, compounds which are known to interact quite specifically with the phosphohydrolase. (d) Under conditions where glucose 6-phosphate and NaF protect the enzyme, no protection is provided against DEPC-mediated inactivation of two other functional components of the membrane, the glucose 6-phosphate translocase and UDP-glucuronyltransferase. DEPC also shows potential for use at 0 degree C as a label for UDP-glucuronyltransferase.
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PMID:Specific inactivation of the phosphohydrolase component of the hepatic microsomal glucose-6-phosphatase system by diethyl pyrocarbonate. 608 98

Glycogen storage disease type Ib has all the clinical manifestations of glycogen storage disease type Ia such as hepatomegaly, growth retardation, bleeding tendency, hypoglycemia, hyperlactacidemia, hyperuricemia, hyperlipidemia, impaired platelet function plus neutropenia. The overall glucose-6-phosphatase activity in disrupted microsomes from liver is normal whereas glucose-6-phosphate translocase, the first enzyme in the glucose-6-phosphate transport system is absent. There is no glucose-6-phosphatase activity in vivo. Recent results show that in granulocytes the glucose-6-phosphate-dependent hexosemonophosphate-shunt is impaired.
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PMID:Glycogen storage disease type Ib. 631 72


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