Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.6.5.4 (SOR)
 720 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have demonstrated in rat adrenal (Natarajan, R.D. and Harding, B.W. (1985) J. Biol. Chem. 260, 3902-3905) that NADH-semidehydroascorbate reductase and ascorbate participate in an electron transport pathway (ETP) supplying reducing equivalents from NADH to cytochrome P-450scc. Here, we demonstrate that this ascorbate dependent ETP also supplies reducing equivalents to cytochrome P-450(11 beta/18) in both rat adrenal and bovine adrenal cortex. The activity is dependent upon addition of catalase or upon 'cold shock' treatment of isolated mitochondria. Comparison of the rates of 11 beta- and 18-hydroxylation supported by this ETP and by the classical pathway supported by various TCA cycle intermediates suggests that in vivo the ascorbate dependent pathway may be essential for maximal flow of reducing equivalents to the mitochondrial hydroxylases. Partial reconstitution of the ascorbate dependent 11 beta/18-hydroxylase activity was achieved with purified bovine outer mitochondrial and inner mitochondrial membranes fortified with supernatant from sonified mitochondria all preincubated with phosphatidyl choline. These preparations no longer require catalase or 'cold shock' treatment. Ascorbate and NADH-semidehydroascorbate reductase are unable to support 17 alpha- or 21-hydroxylase activity in isolated bovine adrenal cortical microsomes whether incubated with purified outer mitochondrial membranes or not.
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PMID:The function of NADH-semidehydroascorbate reductase and ascorbic acid in corticosteroid hydroxylation. 366 95

Redox activities, NADH:ferricyanide reductase, NAD(P)H:cytochrome reductases, and NADH:ascorbate free-radical reductase, are present in endoplasmic reticulum (ER) and glyoxysomal membranes from the endosperm of germinating castor bean (Ricinus comminus L. var Hale). The development of these functions was followed in glyoxysomes and ER isolated on sucrose gradients from castor bean endosperm daily from 0 through 6 days of germination. On a per seed basis, glyoxysomal and ER protein, glyoxysomal and ER membrane redox enzyme activities, and glyoxylate cycle activities peaked at day 4 as did the ER membrane content of cytochrome P-450. NADH:ferricyanide reductase was present in glyoxysomes and ER isolated from dry seed. This activity increased only about twofold in glyoxysomes and threefold in ER during germination relative to the amount of protein in the respective fractions. The other reductases, NADH:cytochrome reductase and NADH:ascorbate free-radical reductase, increased about 10-fold in the ER relative to protein up to 4 to 5 days, then declined. NADPH:cytochrome reductase reached maximum activity relative to protein at day 2 in both organelles. The increases in redox activities during germination indicate that the membranes of the ER and glyoxysome are being enriched with redox proteins during their development. The development of redox functions in glyoxysomes was found to be coordinated with development of the glyoxylate cycle.
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PMID:Development of Endoplasmic Reticulum and Glyoxysomal Membrane Redox Activities during Castor Bean Germination. 1666 25