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)

Despite the wealth of literature concerned with muscle fiber biochemical, ultrastructural and physiological characteristics, little information is available regarding the metabolic enzyme activities of alpha-motoneurons. The present study examines the metabolism of alpha-motoneurons located in the lateral cell column of the rat lumbosacral enlargment with a quantitative histochemical technique. Variation in the activities of alpha-glucan phosphorylase, NADH-diaphorase, succinic dehydrogenase and acid phosphatase were detectable with the photographic densitometry and atomic absorption spectrophotometry technique. No difference in the glycolytic enzyme activity (mitochondrial alpha-glycerophosphate dehydrogenase) was observed. Analysis of lactate dehydrogenase isoenzymes demonstrated the existence of H type isoenzyme in alpha-motoneurons, consistent with other observations indicating predominance of aerobic metabolism within these neurons. The activities of the former enzymes in alpha-motoneurons formed a complete spectrum of activities, distributed unimodally. Smaller motoneurons exhibited the greatest NADH-D and acid phosphatase activities; phosphorylase activity was greatest in larger motoneurons. Significant variation in the enzyme activity of similar-sized motoneurons suggests that the metabolism of the motoneuron is regulated by factors other than cell size. Relationships between motoneuron metabolic enzyme activity and motor unit type are under current investigation.
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PMID:Metabolic variation among rat lumbosacral alpha-motoneurons. 668 5

To determine the effect of a soft diet and aging on the masticatory motor unit, we investigated the morphologic and metabolic properties of the superficial masseter muscle and its motoneurons in rats. Twenty rats were divided into four groups of five rats: rats fed a hard diet until 4 months after birth (hard, young), rats fed a soft diet until 4 months after birth (soft, young), rats fed a hard diet until 22 months after birth (hard, old), and rats fed a soft diet until 22 months after birth (soft, old). The diameter of the fast-twitch oxidative glycolytic muscle fiber was significantly smaller in the soft than the hard, and in the old than the young groups. The glycolytic enzyme (phosphofructokinase) activity of the muscle was significantly weaker in the old than the young group. There was no significant difference in soma diameter of the motoneurons between the soft and hard group, while the diameter was significantly larger in the old than in the young group. There was no significant difference in NADH-diaphorase activity of the motoneurons between the soft and hard group, while significantly less activity was demonstrated in the old than in the young group. The reduction in motor unit activity caused by the soft diet is considered to influence the morphologic and metabolic properties in the superficial masseter muscle but not in its motoneurons. The reduction in the oxidative enzyme activity of motoneurons with aging may occur regardless of the reduction in motor unit activity.
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PMID:Effect of soft diet and aging on rat masseter muscle and its motoneuron. 829 95

Kluyveromyces lactis mutants defective in the glycolytic enzyme phosphoglucose isomerase are able to grow in glucose media and to produce ethanol, but they depend on a functional respiratory chain and do not grow in glucose-antimycin media. We postulate that this is due to the necessity of reoxidizing, in the mitochondria, the NADPH produced by the pentose phosphate pathway, which may be highly active in these mutants in order to bypass the blockade in the phosphoglucose isomerase step. This oxidation would be mediated by a cytoplasmic-side mitochondrial NAD(P)H dehydrogenase that would pass the electrons to ubiquinone. Data supporting this hypothesis are provided.
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PMID:Reoxidation of the NADPH produced by the pentose phosphate pathway is necessary for the utilization of glucose by Kluyveromyces lactis rag2 mutants. 865 69