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)

Microsome fractions from hypocotyls of dark-grown soybean (Glycine max [L.] Merrill) seedlings incorporated myo-inositol into phosphatidylinositol by an exchange reaction stimulated by Mn(2+) (optimum at 10 mm) and cytidine nucleotides (CMP = CDP approximately CTP) but not by Mg(2+) or nucleotides other than cytidine nucleotides. The activity was membrane associated, with an optimum pH of 8, stimulated by auxin, and inhibited by certain thiol reagents or by heating above 40 degrees C. With radioactive inositol, phosphatidylinositol was the only radioactive product. That turnover was by myo-inositol exchange was verified from experiments where unlabeled inositol replaced already incorporated inositol with approximately the same kinetics as for the incorporation of label. Both the incorporation and the displacement reactions were stimulated by Mn(2+) and CMP and both were responsive to auxin with comparable dose dependency. Corresponding exchange activities with choline or ethanolamine were not observed. The phosphatidylinositol-myo-inositol exchange activity was low or absent from plasma membrane, tonoplast, and mitochondria enriched fractions. The activity co-localized on free-flow electrophoresis and aqueous two-phase partition with NADPH cytochrome c reductase and latent IDPase, markers for endoplasmic reticulum and Golgi apparatus, respectively. With microsomes incubated with both ATP and inositol, polyphosphoinositides were unlabeled demonstrating separate locations for the inositol exchange and phosphatidylinositol kinase reactions. Thus, the auxin-responsive inositol turnover activity of soybean membranes is distinct from the usual de novo biosynthetic pathway. It is not the result of a traditional D-type phospholipase and appears not to involve plasma membrane-associated polyphosphoinositide metabolism. It most closely resembles previously described phosphatidylinositol-myo-inositol exchange activities of plant and animal endoplasmic reticulum.
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PMID:Characteristics of a phosphatidylinositol exchange activity of soybean microsomes. 1666 55

Cardiolipin is a major membrane phospholipid in the mitochondria and is essential for cellular energy metabolism mediated through mitochondrial oxidative phosphorylation. Recent studies indicate that it plays a diverse role in cellular metabolism. Eukaryotic cardiolipin is synthesized de novo from phosphatidic acid via the cytidine-5'-diphosphate-1,2-diacyl-sn-glycerol pathway and is deacylated to monolysocardiolipin in order for it to be remodelled into the form that is observed in mitochondrial membranes. This resynthesis of deacylated cardiolipin from monolysocardiolipin occurs via the Barth Syndrome gene product tafazzin and acyllysocardiolipin acyltransferase-1, monolysocardiolipin acyltransferase-1 and the alpha subunit of trifunctional protein. Heart failure is a disease condition in which the amount and type of cardiolipin is altered. Several animal models have been generated to study the role of altered cardiolipin in heart failure. In many of these models loss of the tetralinoleoyl-cardiolipin species is observed during the development of the heart failure. In the doxycycline inducible short hairpin RNA tafazzin knock down mouse, loss of tetralinoleoyl-cardiolipin is associated with a mitochondrial bioenergetic disruption. Reduction in mitochondrial supercomplex formation and NADH dehydrogenase activity within these supercomplexes is observed. Modulation of CL fatty acyl composition may serve as a therapeutic strategy for the treatment of several pathologies including cardiac dysfunction.We propose that increasing cardiolipin may improve mitochondrial function and potentially serve as a therapy for diseases which exhibit mitochondrial dysfunction involving reduced cardiolipin.
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PMID:Cardiolipin metabolism and the role it plays in heart failure and mitochondrial supercomplex formation. 2480 25