Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.6.99.3 (diaphorase)
 5,903 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Interrelationships between the catalytic behavior of glucose-6-phosphatase and the structure of rat-liver microsomal membranes were investigated. 2. Rabbit anti-microsomal serum completely inhibited glucose-6-phosphate hydrolysis in detergent-modified microsomes but showed no inhibitory effect on the enzyme activity of intact or mechanically disrupted vesicles. 2. Controlled proteolysis of intact microsomes using carboxypeptidase A and/or aminopeptidase M largely denatured enzymes situated on the outer surface of the microsomal vesicles such as monodehydroascorbate reductase and cytochrome c reductase. However, it did not affect the glucose-6-phosphatase activity at all, which remained in a latent state within the membrane. 3. Temperature studies on glucose-6-phosphatase have revealed that only the enzyme activity of intact microsomes exhibited a nonlinear Arrhenius plot, whereas detergent-modified microsomes showed a linear temperature response. 4. Treatment of microsomes with phospholipase C and toluene-2,4-diisocyanate resulted in an apparent loss of about 65% and 85% of the original glucose-6-phosphatase activity and was closely correlated with hydrolysis and chemical modification of phosphatidylethanolamine, respectively. These apparent inactivations could be reversed by addition of Triton X-114 alone without any phospholipid supplementation. These observations indicate that glucose-6-phosphatase is buried within the microsomal membrane, not exposed on either side. They also suggest that phospholipids are involved in the glucose-6-phosphate transport mechanism.
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PMID:Investigations on the possible involvement of phospholipids in the glucose-6-phosphate transport system of rat-liver microsomal glucose-6-phosphatase. 624 79

Brush border membrane vesicles from rat small intestine were isolated by a Mg/EGTA precipitation method. Further fractionation either by free flow electrophoresis or by sucrose density gradient centrifugation leads to subfractions which differ with respect to enzyme enrichment factors, transport properties for D-glucose and protein pattern analyzed by sodium dodecyl sulfate/polyacrylamide gel electrophoresis. A relative enrichment of (Na+ + K+)-ATPase is found in one fraction, whereas in another fraction maltase, aminopeptidase M and alkaline phosphatase are relatively enriched. The fractions show different properties of D-glucose transport under tracer exchange conditions and a different inhibition of D-glucose transport by phlorizin and phloretin. These results indicate that the vesicles obtained from rat small intestine by this cation precipitation method are not homogeneous. The inhomogeneity cannot be due to a crosscontamination by membranes other than from the cell envelopment, as none of the fractions show a significant enrichment of succinate--cytochrome c oxidoreductase, KCN-resistant NADH oxidoreductase or glucosaminidase. The inhomogeneity might be due either to a crosscontamination by basal-lateral membranes or to membranes derived from epithelial cells not yet fully differentiated.
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PMID:Heterogeneity of brush-border-membrane vesicles from rat small intestine prepared by a precipitation method using Mg/EGTA. 641 69

We previously demonstrated that the mitochondrial NADH dehydrogenase subunit 2 (ND2) gene was overexpressed in human acute myelogenous leukemia (AML) cells. Since this finding suggested that ND2 gene expression was related to myeloid differentiation, we here investigated the effects of rotenone, a specific NADH dehydrogenase inhibitor, on HL-60 cell growth, differentiation and death. Fifty nM rotenone inhibited the growth of HL-60 cells and caused an increase in the cell population in the G(2) +M phase. In the quantitative comparison of myeloid antigen, the expression of CD13 and CD38 were relatively increased in the rotenone-treated cells. These findings suggest that the inhibition of NADH dehydrogenase changes the cell cycle and induces some specific surface antigens of HL-60 cells. On the other hand, the expression of ND2 gene remained unchanged after the rotenone treatment, suggesting the rotenone-mediated mitochondrial inhibition did not affect the mitochondrial gene expression. Five mu M rotenone strongly inhibited the cellular proliferation. Electron microscopy and an electrophoretic analysis of DNA showed that the majority of the HL-60 cells were induced into typical apoptosis within 24-48 hours. On the basis of this and other studies, we believe that mitochondrial function is directly involved in both cellular differentiation and apoptotic cell death.
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PMID:Rotenone, a mitochondrial NADH dehydrogenase inhibitor, induces cell surface expression of CD13 and CD38 and apoptosis in HL-60 cells. 883 8