Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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 following enzymes have been studied (subcellular fractions are shown between parentheses): NAG and beta-glucuronidase (lysosomes); SDH (mitochondrial); glucose-6-phosphatase (endoplasmic reticulum); 5'-nucleotidase and (Na+, K+)Mg2+ ATPase (plasma membranes). Alterations on their activities were observed after subcutaneous injection of sex hormones, compared with controls. NAG activity from liver was always significantly decreased in lysosomal and microsomal fractions after the hormonal treatment. In the same conditions, NAG from brain was always increased. beta-Glucuronidase behaves like NAG in brain; in liver it was not modified by testosterone and it was slightly increased in lysosomal fraction after oestradiol treatment. SDH activity was not modified in mitochondrial fractions from liver, but this activity was always significantly increased in brain. Glucose-6-phosphatase activity was always significantly decreased in microsomal fractions from liver. It was increased in brain after oestradiol and testosterone injection, but medroxyprogesterone treatment caused a decreased activity. 5'-Nucleotidase and (Na+, K+)Mg2+ ATPase from brain were significantly increased in microsomal fractions by oestradiol and testosterone. Medroxyprogesterone, however, caused an increase in ATPase, but did not affect 5'-nucleotidase. Both activities in liver were decreased by oestradiol and increased by testosterone, but medroxyprogesterone caused (Na+, K+)Mg2+ ATPase to rise and 5'-nucleotidase to fall.
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PMID:Effects of oestradiol, testosterone and medroxyprogesterone on subcellular fraction marker enzyme activities from rat liver and brain. 298 29

The effect of subcutaneous injection of hydrocortisone and corticosterone on the activity values of some subcellular fractions marker enzymes from rat liver and brain was investigated and compared with controls (without treatment with hormones). The following enzymes were studied (subcellular fraction are shown between parentheses): N-acetyl-beta-D-glucosaminidase and beta-glucuronidase (lysosomes); succinate dehydrogenase = SDH (mitochondria); glucose-6-phosphatase (endoplasmic reticulum); 5'-nucleotidase and Na+-K+-Mg2+ ATPase (plasma membrane). The specific activity of lysosomal enzymes from liver showed no change when rats were injected either with hydrocortisone or corticosterone. The same enzymes from brain showed significant increases in their activities with both hydrocortisone or corticosterone except beta-glucuronidase; this enzyme gave activity values remaining between the control levels, after treatment with corticosterone. The activity of mitochondrial SDH was increased after corticosterone injection either in liver or brain. After hydrocortisone injection, its activity rises significantly in brain (72%), but it falls in liver compared to the control values. Glucose-6-phosphatase behaves similarly in brain or liver fractions; its activity increases always after corticosterone treatment and decreases by hydrocortisone. The plasma membrane marker enzymes did not change practically in brain fractions, excepted Na+-K+-Mg2+ ATPase which tends to rise its activity after hydrocortisone injection. In liver fractions, both 5'-nucleotidase and Na+-K+-Mg2+ ATPase activities increase either by corticosterone or hydrocortisone treatment, except 5'-nucleotidase which specific activity decreases in liver after hydrocortisone treatment.
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PMID:Alterations in the activities of subcellular fractions marker enzymes in rat liver and brain by hydrocortisone and corticosterone treatment. 298 17

Hepatic microsomal glucose-6-phosphatase activity levels and the hepatic output of glucose are increased in diabetes. We have used protein chemistry and immunological techniques to determine the mechanism by which the activity levels of the glucose-6-phosphatase system are increased in streptozotocin-induced diabetic rats. In the streptozotocin-induced diabetic rats, the activity of the glucose-6-phosphatase enzyme increased four-fold without appreciably altering the transport capacity of the glucose-6-phosphatase system. The solubilized diabetic rat liver glucose-6-phosphatase enzyme appeared to be very similar to the solubilized enzyme from control rat liver microsomes. They exhibit the same Km, are labile at 30 degrees C, are stabilized by sodium fluoride and they migrate to the same position during density gradient centrifugation. Immunological studies demonstrated that a greater amount of hepatic microsomal glucose-6-phosphatase enzyme protein is present in diabetic rats than in control rats. Thus, we have determined for the first time that increased levels of the glucose-6-phosphatase protein are present in streptozotocin-induced diabetes. The significance of this finding in relation to the regulation of the hepatic microsomal glucose-6-phosphatase system is discussed.
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PMID:Rat hepatic microsomal glucose-6-phosphatase protein levels are increased in streptozotocin-induced diabetes. 300 90

The subcellular localization of cathepsin B activity (EC 3.4.22.1) in three murine melanomas of increasing metastatic potential (Cloudman less than B16-F1 less than B16 amelanotic) was determined. Cathepsin B activity was localized in the heavy mitochondrial fraction of normal murine liver but in the light mitochondrial fraction of the metastatic melanomas; the localization of three other lysosomal hydrolases did not shift. Further purification of the light mitochondrial fraction into L-1 (density = 1.045 g/ml) and L-2 (density = 1.07 g/ml) fractions was achieved on a 30% iso-osmotic Percoll gradient. The L-1 fraction of liver and melanomas contained Na+, K+-ATPase activity; the L-2 fraction of liver contained four lysosomal hydrolase (cathepsins B and H, N-acetyl-beta-glucosaminidase, and beta-glucuronidase) and glucose-6-phosphatase activities. Ultrastructural examination revealed that the L-1 fraction consisted of membrane vesicles and the L-2 fraction of secondary lysosomes. In the B16 melanomas cathepsin B and N-acetyl-beta-glucosaminidase activities were found in both L-1 and L-2 fractions. Specific activities of the two enzymes in the plasma membrane (L-1) fractions increased in correspondence with metastatic potential. Cathepsin H and beta-glucuronidase activities were not localized in the plasma membrane fractions of the B16 melanomas. Localization of hydrolytic enzymes in the plasma membrane of metastatic tumor cells could result in focal dissolution of the extracellular matrix and thereby invasion and metastasis.
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PMID:Cathepsin B: association with plasma membrane in metastatic tumors. 345 10

Plasma membrane vesicles isolated from rat liver exhibited an azide-insensitive Mg2+-ATP-dependent Ca2+ pump which accumulated Ca2+ at a rate of 5.1 +/- 0.5 nmol of calcium/mg of protein/min and reached a total accumulation of 33.2 +/- 2.6 nmol of calcium/mg of protein in 20 microM Ca2+ at 37 degrees C. Equiosmotic addition of 50 mM Na+ resulted in a loss of accumulated calcium. Measurement of Mg2+-ATP-dependent Ca2+ uptake in the presence of 50 mM Na+ revealed no effect of Na+ on the initial rate of Ca2+ uptake, but a decrease in the total accumulation. The half-maximal effect of Na+ on Ca2+ accumulation was achieved at 14 mM. The Ca2+ efflux rate constant in the absence of Na+ was 0.16 +/- 0.01 min-1, whereas the efflux rate constant in the presence of 50 mM Na+ was 0.25 +/- 0.02 min-1. Liver homogenate sedimentation fractions from 1,500 to 105,000 X g were assayed for azide-insensitive Mg2+-ATP-dependent Ca2+ accumulation. Na+-sensitive Ca2+ uptake activity was found to specifically co-sediment with the plasma membrane-associated enzymes, 5'-nucleotidase and Na+/K+-ATPase, whereas Na+-insensitive Ca2+ uptake was found to co-sediment with the endoplasmic reticulum-associated enzyme, glucose-6-phosphatase. The plasma membrane Ca2+ pump was also distinguished from the endoplasmic reticulum Ca2+ pump by its sensitivity to inhibition by vanadate. Half-maximal inhibition of plasma membrane Ca2+ uptake occurred at 0.8 microM VO4(3-), whereas half-maximal inhibition of microsomal Ca2+ uptake occurred at 40 microM.
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PMID:Liver plasma membrane calcium transport. Evidence for a Na+-dependent Ca2+ flux. 348 13

Twenty four hour urine samples of male control and streptozotocin-diabetic Wistar rats were analysed for a series of commonly known kidney-specific enzymes, for electrolytes, creatinine, glucose, total protein and urine volume. The examination was done during two periods of 5 days between the 25th and 30th and the 32nd and 36th day after streptozotocin application. In the first period the animals had free access to food and water, whereas in the second period on days 32, 34 and 36 food was withdrawn. In the first observation period the diabetic rats showed increased excretion rates of 15 measured urinary parameters, while alanine aminopeptidase (EC 3.4.1.2) and gamma-glutamyltransferase (EC 2.3.2.2) activities were lowered and inorganic phosphate was unchanged. The removal of food resulted in decreased excretion values for alanine aminopeptidase, gamma-glutamyltransferase and total protein as compared with fasted nondiabetic animals. The activities of N-acetyl-beta-D-glucosaminidase (EC 3.2.1.30), acid phosphatase (EC 3.1.3.2), lactate dehydrogenase (EC 1.1.1.27), pyruvate kinase (EC 2.7.1.40), C1-fructose 1.6-diphosphatase (EC 3.1.3.11) and the excretion values for sodium, calcium, magnesium, chloride and glucose were higher than in fasted nondiabetic rats. beta-Glucosidase (EC 3.2.1.21), potassium, inorganic phosphate, creatinine, and urine volume showed no differences between fasted diabetic and fasted control animals. The enzymes in the renal cortex at the end of the experiment showed only decreased activity of alanine aminopeptidase in diabetic rats. Lactate dehydrogenase, pyruvate kinase, beta-glucosidase, C1-fructose 1.6-diphosphatase and glucose 6-phosphatase (EC 3.1.3.9) were increased and gamma-glutamyltransferase, N-acetyl-beta-D-glucosaminidase, acid phosphatase and glucose 6-phosphate dehydrogenase (EC 1.1.1.49) showed no change.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Enzymuria in streptozotocin-diabetic rats. 353 86

Basolateral membrane vesicles were isolated from the rat kidney cortex by a modified method of cation precipitation. Different steps of preparation were analysed using the marker enzymes: Na+,K+-ATPase (for basolateral membrane), alkaline phosphatase (for apical membrane), glucose-6-phosphatase (for membranes of endoplasmic reticulum) and succinate dehydrogenase (for mitochondria). The basolateral membrane was purified by a 8-9-fold treatment with Na+,K+-ATPase, while other membrane contaminations were as low as 2% (as compared to homogenate). The transport of 3H-p-aminohippurate (3H-PAH) by basolateral membrane vesicles was measured under different experimental conditions. The 3H-PAH uptake was found to be Na-gradient dependent. The initial rate of 3H-PAH uptake in the presence of NaCl gradient (500 pM/mg X min) was higher than without the gradient (88 pM/mg X min). It is concluded that the PAH transfer across the basolateral membrane may be energized by the Na+ chemical gradient.
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PMID:[Effect of a NaCl gradient on the transport of para-aminohippuric acid into the vesicles of the basolateral membrane of the kidney cortex]. 359 Mar 16

Hematological, biochemical, histoenzymological, and histopathological changes in serum and tissues were studied in chickens during outbreaks of nephritis. Hematological studies revealed normocytic-normochromic anemia characterized by increased total erythrocyte counts, hemoglobin, packed cell volume, and erythrocyte sedimentation rate. Albumin-to-globulin ratio and sodium levels in serum, glucose in blood, and alkaline phosphatase and glucose-6-phosphatase in liver and kidneys were decreased. Glutamate pyruvate transaminase, uric acid, non-protein-nitrogen, and potassium levels in serum were increased. No significant change in the calcium, phosphorus, and total protein levels in serum was observed. These changes were directly related to the severity of the nephritis.
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PMID:Clinicopathological, hematological, and biochemical studies in some outbreaks of nephritis in poultry. 407 33

In order to evaluate the possible role of sodium- and potassium-activated adenosine triphosphatase in the active transport of sodium by the renal tubules, we examined the effect of large changes in the tubular reabsorptive load of sodium on the Na-K-ATPase activity of rat kidney homogenates. Glomerular filtration and tubular reabsorption of sodium per gram of kidney tissue increased progressively after contralateral uninephrectomy. This was paralleled by an increase in Na-K-ATPase per milligram of protein in a microsomal fraction of kidney cortex. The importance of this change is underlined by the absence of simultaneous increases in other microsomal enzymes such as glucose-6-phosphatase and Mg(++)-dependent ATPase, or in succinic dehydrogenase or glutaminase. Similar increases in Na-K-ATPase were observed when the net tubular reabsorption of sodium was increased by feeding the animals a high-protein diet or after injection of methylprednisolone. On the other hand, Na-K-ATPase was lowered when tubular transport of sodium was reduced by bilateral adrenalectomy. The results of these experiments show that renal Na-K-ATPase changes in an adaptive way when renal reabsorption of sodium is chronically increased or diminished and support the hypothesis that this enzyme system is involved in the process by which sodium is actively transported across the renal tubule.
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PMID:The role of sodium-potassium-activated adenosine triphosphatase in the reabsorption of sodium by the kidney. 429 72

Experiments were done on rats to investigate the nature of the renal response to metabolic acidosis and the changes in enzyme activity associated with increased ammoniagenesis. When metabolic acidosis was induced with oral feeding of ammonium chloride for 48 hr, there was an increase of activity of the enzyme phosphoenolpyruvate carboxykinase (PEPCK) in whole kidneys as well as in the kidney cortex. There was no change in PEPCK in liver, and glucose-6-phosphatase showed no change in kidney or liver in response to metabolic acidosis. The increase in PEPCK activity in kidney cortex varied with the degree of acidosis and there was a close correlation between cortical PEPCK activity and urinary ammonia. Kidney cortex mitochondrial PEPCK did not change in response to metabolic acidosis. An increase in PEPCK occurred as early as 6 hr after NH(4)Cl feeding, before there was any increase in kidney glutaminase I activity. Rats fed sodium phosphate, or given triamcinolone intramuscularly, developed a metabolic alkalosis, but there was increased urinary ammonia and an increase in activity of renal cortical PEPCK. Triamcinolone plus ammonium chloride induced a greater increase of PEPCK activity than triamcinolone by itself; on the contrary, the rise of glucose-6-phosphatase induced by triamcinolone was not enhanced by acidosis. Glucose-6-phosphatase from control and acidotic rats had identical kinetic characteristics. The results indicate that increased PEPCK activity is constantly related to increases of urinary ammonia. It is proposed that the increase of PEPCK activity is the key event in the ammoniagenesis and gluconeogenesis which follow on metabolic acidosis.
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PMID:Renal metabolic response to acid base changes. I. Enzymatic control of ammoniagenesis in the rat. 430 57


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