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:3.1.3.1 (alkaline phosphatase)
47,916 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Treatment of rat liver microsomes with alkaline phosphatase results in a loss in the FMN but not the FAD flavin prosthetic group of NADPH-cytochrome P-450 reductase (Taniguchi, H. and Pyerin, W. (1987) Biochim. Biophys. Acta 912, 295-307). Experiments were carried out to evaluate the effect of preventing electron transfer from the FADH2 to FMN component of the reductase, and subsequent mixed function oxidase activity, on reduction of ferric chelates, production of H2O2, and the generation of .OH-like species by microsomes. Treatment with alkaline phosphatase was confirmed to decrease NADPH-cytochrome c, but not NADPH-ferricyanide, reductase activity by microsomes and by purified NADPH cytochrome P-450 reductase. The oxidation of hydroxyl radical scavenging agents by microsomes and reductase was decreased by the alkaline phosphatase treatment in accordance with the decline in cytochrome c reductase activity. This decrease in hydroxyl radical production occurred in the presence of various ferric chelate catalysts. Rates of microsomal reduction of the ferric chelates were also inhibited after alkaline phosphatase treatment. Production of H2O2 was decreased in accordance to the fall in cytochrome c reductase activity and .OH production. Rates of H2O2 production appeared to be rate-limiting for the overall generation of .OH as the addition of an external H2O2-generating system stimulated .OH production as well as prevented the decline in .OH production caused by the alkaline phosphatase treatment. These results suggest that both the FAD and FMN flavin prosthetic groups of the reductase contribute towards the reduction of various ferric chelates. However, loss of the FMN component and activities dependent on electron transfer from this prosthetic group result in a decrease in H2O2 production, which appears to be responsible for the decline in the generation of .OH-like species by microsomes after treatment with alkaline phosphatase.
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PMID:Inhibition of the oxidation of hydroxyl radical scavenging agents after alkaline phosphatase treatment of rat liver microsomes. 190 77

Oral administration of embelin (75 mg/kg per day, daily for 15 and 30 days) to male rats caused significant elevation in the uptake of D-glucose, L-alanine, L-leucine and calcium in small intestinal segments. Embelin also produced significant increases in intestinal brush border membrane-associated enzymes (sucrase, lactase, maltase, alkaline phosphatase and leucine aminopeptidase) in both intestinal homogenates and partially purified brush border membrane preparations. Significant increases were also noted for microsomal glucose-6-phosphatase and cytosolic lactate dehydrogenase. Increase in brush border membrane-associated total lipids, phospholipids, cholesterol, triacylglycerol, unesterified fatty acids and ganglioside sialic acid were seen but not in the cholesterol/phospholipid molar ratio. All these changes returned to control or near control levels following withdrawal of the drug.
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PMID:Effects of embelin, a male antifertility agent, on absorptive and digestive functions of rat intestine. 192 15

Thirteen patients with epilepsy on long-term antiepileptic drug therapy and who had a persistently raised serum alkaline phosphatase (ALP) activity were investigated biochemically. Twelve patients had a raised liver ALP-isoenzyme activity and in nine of these the bone ALP-isoenzyme activity was normal. Gamma-glutamyl transferase (gamma GT) levels were raised in 12 patients. Two patients were hypoglycaemic. One patient fitted the biochemical parameters for subclinical osteomalacia. The resultant clinical picture showed 75% of patients with borderline hypocalcaemia, raised liver ALP, raised gamma GT and normal bone ALP activities in whom 1,25 dihydroxy-cholecalciferol (1,25-DHCC; vitamin D) therapy would be inappropriate, whilst 1,25-DHCC therapy might be considered for those with borderline hypocalcaemia and a raised bone ALP activity (three patients). No evidence was found of hepatotoxicity or drug induced cholestasis. It is considered that the induction of liver microsomal enzymes by antiepileptic drugs could include liver ALP (as opposed to bone ALP) as well as gamma GT and the inactivation pathways for 1,25 DHCC.
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PMID:Antiepileptic drugs, hepatic enzyme induction and raised serum alkaline phosphatase isoenzymes. 198 78

Thioacetamide (100 mg/kg), when administered to normal rats, caused a significant increase in the activities of 5'-nucleotidase and gamma-glutamyl transpeptidase and a decrease in the activities of glucose 6-phosphatase and succinate dehydrogenase enzymes in the liver. DNA, RNA, and proteins were increased while the cytochrome P450 in the microsomal fraction and the glycogen content in the liver were decreased significantly. Elevations in the activities of GOT, GPT, and alkaline phosphatase and bilirubin content in serum were also observed. Picroliv, a standardised glycoside fraction of Picrorhiza kurroa, in doses of 12.5 and 25 mg/kg prevented most of the biochemical changes induced by thioacetamide in liver and serum. The hepatoprotective activity of Picroliv was comparable with that of silymarin, a known hepatoprotective agent obtained from seeds of Silybum marianum.
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PMID:Picroliv affords protection against thioacetamide-induced hepatic damage in rats. 206 53

Most of L-asparaginase activity of Tetrahymena pyriformis was found to be present in microsomal membranes from which it has been purified to homogeneity (Tsirka, S.A.E. and Kyriakidis, D.A. Mol. Cell. Biochem. 83: 147-155, 1988). The native enzyme has a relative molecular weight of approximately 200 kDa, while under denaturing conditions the enzyme exhibits a subunit size of 39 kDa. Aminoacid analysis and an oligopeptide from N-terminal sequence have been determined. Dephosphorylation of L-asparaginase by alkaline phosphatase results in an activation of its catalytic activity. This enzyme also exhibits intrinsic phosphorylation activity with a Km value for ATP of 0.5 mM. Autophosphorylation with [gamma-32P] ATP of purified L-asparaginase results in the phosphorylation of tyrosine residues as well as in loss of its activity. Mg2+ and Ca2+ added together act synergistically to stimulate the kinase activity by more than 160%. The polyamines putrescine, spermidine and spermine activate the kinase approximately 100%, while neither cAMP or cGMP have any effect. These results indicate that this membrane protein with dual L-asparaginase/kinase activity must play an important role in regulating the intracellular levels of L-asparagine in Tetrahymena pyriformis.
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PMID:L-asparaginase of Tetrahymena pyriformis is associated with a kinase activity. 211 26

Administration of Embelin, an experimental antifertility agent, to male rats (20 mg/kg body wt/day, daily for 15 and 30 days), caused an elevation in the uptake of D-glucose, L-alanine, L-leucine, and calcium in the small intestinal segments. An increase was also noted in the intestinal brush border membrane (BBM)-associated enzymes, sucrase, lactase, maltase, alkaline phosphatase, and leucine aminopeptidase in both the intestinal homogenates and partially purified BBM preparations, particularly after 30-day administration of the drug. Embelin treatment also caused a significant increase in the microsomal glucose-6-phosphatase and the cytosolic enzyme, lactate dehydrogenase. In the Embelin-treated animals BBM-associated total lipids, phospholipids, cholesterol, triacylglycerol, unesterified fatty acids, ganglioside-sialic acids as well as the cholesterol/phospholipids molar ratio showed a considerable increase. All these changes in the Embelin-treated animals were restored back to the normal or near normal biochemical makeup when the drug therapy was withdrawn and the animals were allowed to recover for another 15 and 30 days, respectively.
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PMID:Changes in glucose/amino acid/calcium uptake and brush-border membrane-associated enzymes in rat small intestine after the administration of embelin (plant benzoquinone), an antifertility agent. 211 47

A number of morphological and functional changes on liver cells were reported during experimental cholestasis. Some specific metabolic pathways catalyzed by "membrane bound" enzymes were described to be altered by lipid microenvironment changes. The purpose of he present study is to establish Bilirubin UDP-Glucuronyltransferase activity--a microsomal integral enzyme responsible for bilirubin conjugation--and microsomal phospholipid profile in cholestatic and normal patients. Surgical liver biopsies were taken fron five patients suffering prolonged extrahepatic cholestasis, and five patients submitted to abdominal surgery excluding hepato-biliary diseases that were considered as controls. The following biochemical parameters were determined in both groups: bilirubin concentration, alkaline phosphatase, gamma-glutamyltranspeptidase, oxalacetic and pyruvic transaminases, and pseudo-cholinesterase activities. Serum cholestatic markers showed significative increments in cholestatic patients (Table 1). Total Bilirubin UDP-Glucuronyltransferase activity was similar comparing normal and cholestatic individuals (1.11 +/- 0.66 and 1.93 +/- 0.82 nmol conjugated bilirubin/mg protein in 10 min. respectively). When final reaction product was analysed, the normal group showed 80% of bilirubin diglucuronide; but resulted undetectable in cholestatic patients yielding 100% of bilirubin monoglucuronide. Microsomal phospholipid analysis showed a decrease in phosphatidylcholine and phosphatidylethanolamine contents in the cholestatic group; probably due to the action of bile acids accumulated into the hepatic cells. Simultaneously we found an increment in phosphatidylserine and sphingomyelin levels in cholestatic patients compared to normals (Figure 1). This fact could be explained by the existence of special sites in the membrane for the latter phospholipids, protected against bile acids detersive action.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Phospholipid composition of the hepatic microsomal membrane and its relationship to bilirubin UDP glucuronyltransferase in human cholestasis]. 213 64

Rabbit adrenal 17 alpha-hydroxylase activity has previously been shown to increase dramatically following ACTH stimulation. The present study was designed to determine whether the increase in enzyme activity could be correlated with an increase in P-450(17 alpha) protein measured by immunoblotting using an anti-porcine P-450(17 alpha) antibody. It was found that the total and specific contents of rabbit adrenal immunoreactive P-450(17 alpha) were increased 6- to 8-fold and 4-fold, respectively, after ACTH stimulation. The results were similar whether the detection system was 125I-labeled protein A or an alkaline phosphatase-conjugated second antibody. Corresponding increases in 17 alpha-hydroxylase activity were also observed but were slightly less than the increases in immunoreactive P-450(17 alpha), suggesting that not all of the protein was enzymatically active. Comparatively, immunoreactive P-450(21) was increased only 1.3-fold. Antibodies to porcine P-450(17 alpha) and bovine P-450(21) reacted monospecifically with the homologous rabbit and guinea pig proteins as judged by the detection of single bands on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Inhibition studies showed that in an assay using 125 micrograms per ml of microsomal protein ACTH-stimulated rabbit adrenal 17 alpha-hydroxylase activity was inhibited 72% at a 100 mg per ml concentration of the anti-porcine P-450(17 alpha); however, 47% inhibition was observed at the same concentration of anti-bovine P-450(21). Pre-immune IgG had no effect. Molecular weight, Mr, determinations by SDS-PAGE showed both rabbit and guinea pig P-450(17 alpha) to be 52 kDa; rabbit P-450(21), 54 kDa; and guinea pig P-450(21), 49 kDa.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:ACTH-induced increases in rabbit adrenal immunoreactive P-450(17 alpha) and P-450(21). 215 89

Apical plasma membrane vesicles were prepared from human organ donor colon mucosal scrapings. These vesicles were enriched 10-fold in cysteine-sensitive alkaline phosphatase activity compared to starting homogenates, and showed minimal contamination of microsomal, mitochondrial or basolateral membranes. Transport studies using [22Na] uptake into proximal colonic vesicles demonstrated Na+ and H+ conductances, Na+/H+ exchange and amiloride inhibition of Na+ uptake. The isolation of these apical vesicles will permit detailed study of human colonic transport processes.
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PMID:Apical plasma membrane vesicles formed from organ donor colon demonstrate Na+ and H+ conductances and Na+/H+ exchange. 215 6

Treatment of PC12 cells with nerve growth factor (NGF) resulted in the rapid, but transient, activation of a protein kinase which specifically phosphorylated an endogenous 250-kDa cytoskeletal protein (pp250). We report that the microtubule-associated protein, MAP2, is an alternative substrate for the NGF-activated kinase. NGF treatment maximally activated the kinase within 5 min; however, the activity declined with longer exposure to NGF. The enzyme was localized predominantly in microsomal and soluble fractions and phosphorylated MAP2 on serine and threonine residues. The soluble enzyme was fractionated by DEAE chromatography and gel filtration and had an apparent Mr of 45,000. The enzyme was purified to near homogeneity by chromatofocussing and had a pI of 4.9. Kinetic analysis revealed that NGF treatment caused a sevenfold increase in Vmax for MAP2. The Km with respect to the MAP2 substrate was approximately 50 nM and was not altered by NGF treatment. A novel feature of the NGF-stimulated enzyme was its sharp dependence on Mn2+ concentration. The active enzyme is likely to be phosphorylated, because inclusion of phosphatase inhibitors was required for recovery of optimal activity and the activity was lost on treatment of the enzyme with alkaline phosphatase. Histones, tubulin, casein, bovine serum albumin, and the ribosomal subunit protein S-6 were not phosphorylated by this enzyme. The NGF-stimulated kinase was distinct from A kinase, C kinase, or other NGF-stimulated kinases. The rapid and transient activation of the protein kinase upon NGF treatment suggests that the enzyme may play a role in signal transduction in PC12 cells.
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PMID:Characterization of a nerve growth factor-stimulated protein kinase in PC12 cells which phosphorylates microtubule-associated protein 2 and pp250. 216 72


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