Inhibition of Glucose 6-Phosphate Dehydrogenase by Palmitoyl Coenzyme A*
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چکیده
Low concentrations of palmitoyl coenzyme A inhibit yeast glucose-6-P dehydrogenase (TAKETA, K., AND POGELL, B. M. (1966) J. Biol. Chem. 241, 720). This inhibition is prevented or reversed by bovine serum albumin, mycobacterial polysaccharides, or alkylated cyclodextrins. Sephadex chromatography and sucrose density gradient centrifugation show that palmitoyl-CoA inhibits by dissociating the tetramerit dehydrogenase to dimeric, enzymatically inactive subunits. These structural changes are accompanied by firm binding of palmitoyl-CoA to the dimeric subunit and by release of NADP. After removal of the (nondialyzable) inhibitor from the pahnitoyl-CoA-dimer complex by alkylated cyclodextrin the subunits reaggregate to enzymatically active tetramer. Reaggregation does not require NADP. In contrast to palmitoyl-CoA, sodium dodecyl sulfate dissociates yeast dehydrogenase to monomers. It is concluded that palmitoyl-CoA, unlike the synthetic anionic detergent, perturbs the dehydrogenase subunit structure in a controlled manner which may be important for regulating the activity of lipogenic enzymes. The dimeric glucose-6-P dehydrogenase from Leuconostoc mesenteroides is inhibited only by high concentrations of palmitoyl-CoA. In this instance palmitoyl-CoA neither binds to the enzyme nor dissociates it. Torutopsis utilis glucose-6-P dehydrogenase, also dimeric, is irreversibly converted to inactive monomers by low concentrations of palmitoyl-CoA.
منابع مشابه
Inhibition of Glucose 6-Phosphate Dehydrogenase by Palmitoyl Coenzyme A*
Low concentrations of palmitoyl coenzyme A inhibit yeast glucose-6-P dehydrogenase (TAKETA, K., AND POGELL, B. M. (1966) J. Biol. Chem. 241, 720). This inhibition is prevented or reversed by bovine serum albumin, mycobacterial polysaccharides, or alkylated cyclodextrins. Sephadex chromatography and sucrose density gradient centrifugation show that palmitoyl-CoA inhibits by dissociating the tetr...
متن کاملInhibition of glucose 6-phosphate dehydrogenase by palmitoyl coenzyme A.
Low concentrations of palmitoyl coenzyme A inhibit yeast glucose-6-P dehydrogenase (TAKETA, K., AND POGELL, B. M. (1966) J. Biol. Chem. 241, 720). This inhibition is prevented or reversed by bovine serum albumin, mycobacterial polysaccharides, or alkylated cyclodextrins. Sephadex chromatography and sucrose density gradient centrifugation show that palmitoyl-CoA inhibits by dissociating the tetr...
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Purification and properties of Penicillium glucose 6-phosphate dehydrogenase.
1. Glucose 6-phosphate dehydrogenase was isolated and partially purified from a thermophilic fungus, Penicillium duponti, and a mesophilic fungus, Penicillium notatum. 2. The molecular weight of the P. duponti enzyme was found to be 120000+/-10000 by gelfiltration and sucrose-density-gradient-centrifugation techniques. No NADP(+)- or glucose 6-phosphate-induced change in molecular weight could ...
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تاریخ انتشار 2003