Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.6.99.5 (NADH dehydrogenase)
 2,135 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A previously described histochemical technique was applied to the localization of rhodanese (thiosulfate sulfurtransferase, EC 2.8.1.1) activity in rat skeletal muscle and liver. The physiological function of rhodanese is controversial, but it and other sulfurtransferases can catalyze the conversion of cyanide to the much less toxic thiocyanate. The volume of distribution of cyanide in human and dog is said to correspond roughly to the blood volume. Because of this and other observations, it was hypothesized that sulfurtransferase activity associated with the vascular endothelium on smooth muscle layers of blood vessels might play a role in cyanide detoxification. However, little enzyme activity as identified histochemically was associated with those sites in comparison with others examined. As expected, high activity was found in the liver and moderately high levels were present in skeletal muscle. In muscles sectioned longitudinally, points of rhodanese staining occurred in linear arrays along the lengths of the muscle fiber corresponding to the location of mitochondria within the fiber. The original technique called for incubation of tissue sections with both thiosulfate and cyanide. When thiosulfate was omitted, staining for rhodanese activity was still clearly identifiable in both liver and muscle sections with cyanide alone. In muscle sections the inclusion of both thiosulfate and cyanide resulted in a preferential staining of type I fibers presumably because of their higher content of mitochondria. Thus, this technique is a potential alternative to the NADH dehydrogenase stain for distinguishing between type I and type II muscle fibers. Incubation of tissue sections with only thiosulfate produced results that did not appear to differ from those obtained when both substrates were omitted. From these observations it may be inferred that the endogenous pool of sulfane-sulfur available to sulfurtransferases is larger than any alleged endogenous pool of cyanide. Although sulfurtransferase activity in muscle appeared to be lower than that in liver, the total body muscle mass is greater than the liver mass. Thus, these results support other evidence that skeletal muscle may make a significant contribution to total cyanide biotransformation in the absence of exogenously added thiosulfate.
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PMID:Histochemical localization of rhodanese activity in rat liver and skeletal muscle. 292 57

The cyclic AMP receptor protein family of transcription factors regulates various metabolic pathways in bacteria, and also play roles in response to environmental changes. Here, we identify four homologs of the CRP family in Deinococcus radiodurans, one of which tolerates extremely high levels of oxidative stress and DNA-damaging reagents. Transcriptional levels of CRP were increased under hydrogen peroxide (H2O2) treatment during the stationary growth phase, indicating that CRPs function in response to oxidative stress. By constructing all CRP single knockout mutants, we found that the dr0997 mutant showed the lowest tolerance toward H2O2, ultraviolet radiation, ionizing radiation, and mitomycin C, while the phenotypes of the dr2362, dr0834, and dr1646 mutants showed slight or no significant differences from those of the wild-type strain. Taking advantage of the conservation of the CRP-binding site in many bacteria, we found that transcription of 18 genes, including genes encoding chromosome-partitioning protein (dr0998), Lon proteases (dr0349 and dr1974), NADH-quinone oxidoreductase (dr1506), thiosulfate sulfurtransferase (dr2531), the DNA repair protein UvsE (dr1819), PprA (dra0346), and RecN (dr1447), are directly regulated by DR0997. Quantitative real-time polymerase chain reaction (qRT-PCR) analyses showed that certain genes involved in anti-oxidative responses, DNA repair, and various cellular pathways are transcriptionally attenuated in the dr0997 mutant. Interestingly, DR0997 also regulate the transcriptional levels of all CRP genes in this bacterium. These data suggest that DR0997 contributes to the extreme stress resistance of D. radiodurans via its regulatory role in multiple cellular pathways, such as anti-oxidation and DNA repair pathways.
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PMID:Cyclic AMP Receptor Protein Acts as a Transcription Regulator in Response to Stresses in Deinococcus radiodurans. 2718