Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.6.5.2 (NQO1)
 6,196 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. Like the malate dehydrogenases of eucaryotic cells, the Propionibacterium shermanii enzyme is a dimer consisting of two 35,000 molecular weight subunits. 2. In electrophoretic behavior, resistance to substrate inhibition and stability to heating and dilution the P. shermanii MDH is more similar to the s-MDH than to the m-MDH of pig heart. 3. The P. shermanii MDH has a high turnover number (ca. 140,000) as well as Km values for both L-malate and oxalacetate which are four times higher than the mammalian isoenzymes. 4. A coupled assay for MDH using the malate-lactate transhydrogenase and diaphorase is described in which both substrates, L-malate and NAD, are regenerated.
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PMID:A comparison of the malate dehydrogenase of the propionic acid bacteria with the mammalian soluble and mitochondrial isoenzymes. 31 44

Resolution of the fumarate reductase complex (ABCD) of Escherichia coli into reconstitutively active enzyme (AB) and a detergent preparation containing peptides C and D resulted in loss of quinone reductase activity, but the phenazine methosulfate or fumarate reductase activity of the enzyme was unaffected. An essential role for peptides C and D in quinone reduction was confirmed by restoration of this activity on recombination of the respective preparations. Neither peptide C nor peptide D by itself proved capable of permitting quinone reduction and membrane binding by the enzyme when E. coli cells were transformed with plasmids coding for the enzyme and the particular peptides. Transformation of a plasmid coding for all subunits resulted in a 30-fold increase in membrane-bound complex, which exhibited, however, turnover numbers for succinate oxidation and fumarate reduction that were intermediate between the high values characteristic of chromosomally produced complex and the relatively low values found for the isolated complex. It is also shown that preparations of the isolated complex and membrane-bound form of the enzyme, as obtained from anaerobically grown cells, are in the deactivated state owing to the presence of tightly bound oxalacetate and thus must be activated prior to assay.
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PMID:Reconstitution of quinone reduction and characterization of Escherichia coli fumarate reductase activity. 351 Oct 50