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N J Watmough M A Birch-Machin L A Bindoff A Aynsley-Green K Simpson C I Ragan H S Sherratt D M Turnbull 《Biochemical and biophysical research communications》1989,160(2):623-627
Deficiency of complex I is one of the most commonly reported defects of the mitochondrial respiratory chain in man. Clinical evidence of tissue specific expression of complex I deficiency has not previously been confirmed biochemically. We report here slow oxidation of NAD+-linked substrates, low activity of complex I and low amounts of immunoreactive complex I peptides in skeletal muscle mitochondria from a patient with muscle weakness and lactic acidosis. In liver mitochondria complex I activity was normal and all the immunoreactive subunits of complex I were present in normal amounts. 相似文献
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H2-uptake positive strains (122 DES and SR) and H2-uptake negative strains SR2 and SR3 of Rhizobium japonicum were examined for ribulosebisphosphate (RuBP) carboxylase and H2-uptake activities during growth conditions which induced formation of the hydrogenase system. The rate of 14CO2 uptake by hydrogenase-derepressed cells was about 6-times greater in the presence than in the absence of H2. RuBP carboxylase activity was observed in free-living R. japonicum strains 122 DES or SR only when the cells were derepressed for their hydrogenase system. Hydrogenase and RuBP carboxylase activities were coordinately induced by H2 and both were repressed by added succinate. Hydrogenase-negative mutant strains SR2 and SR3 derived from R. japonicum SR showed no detecyable RuBP carboxylase activities under hydrogenase derepression conditions. No detectable RuBP carboxylase was observed in bacteroids formed by H2-uptake positive strains R. japonicum 122 DES or SR. Propionyl CoA carboxylase activity was consistently observed in extracts of cells from free-living cultures of R. japonicum but activity was not appreciably influenced by the addition of H2. Neither phosphoenolpyruvate carboxylase nor phosphoenolpyruvate carboxykinase activity was detected in extracts of R. japonicum.Abbreviations RuBP
Ribulose 1,5-bisphosphate
- (Na2EDTA)
(Ethylenedinitrilo)-tetraacetic acid, disodium salt
- (propionyl CoA)
Propionyl coenzyme A
- (PEP)
Phosphoenolpyruvate
- (GSH)
Reduced glutathione
- (Tricine)
N-tris(hydroxymethyl)-methylglycine 相似文献
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An alternating conformation characterizes the phosphodiester backbone of poly(dA-dT) in solution. 总被引:10,自引:0,他引:10
A highly homogeneous 145-base-pair fragment of double helical poly(dA-dT) . poly(dA-dT) was obtained by micrococcal nuclease digestion of a semisynthetic chromatin prepared from the nucleosome core histones (H2A, H2B, H3, H4) and the synthetic polydeoxyribonucleotide. In contrast to higher molecular weight alternating copolymers, this fragment displayed two resolved 31P NMR signals, separated by 24 Hz at 10.93 MHz. The two signals were of equal intensity at all temperatures less than the Tm for the fragment. Analyses of the possible origins for the two reasonances leads to the conclusion that the phosphodiester backbone of this DNA contains two distinct phosphorus environments, probably in an alternating array. We suggest that this may indicate the presence of sequence-dependent local variation in the helical structure of DNA in general. 相似文献