Electronic Resource
Springer
Archives of microbiology
93 (1973), S. 13-22
ISSN:
1432-072X
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Summary 1. Membranes fromKlebsiella aerogenes were used to study the reaction site and possible functional heterogeneity of ubiquinone participating in electron transport to both oxygen and nitrate. 2. Ubiquinone-8 was found to be present in great molar excess as compared with the other electron transport carriers. Pentane extraction of ubiquinoe resulted in a decrease in the level of reduction of cytochromeb in the aerobic steady state in the nitrate reducing steady state. 3. Succinate and formate oxidase activities were less strongly inactivated than was the activity of reduced nicotinamide adenine dinucleotide (NADH) oxidase by partial removal or destruction of endogenous ubiquinone. The succinate and formate oxidase activities in ubiquinone-depleted membranes were fully restored on titration with ubiquinone homologs at much lower quinone concentrations than was the NADH oxidase activity. This suggests that less ubiquinone is required to support the maximal rate of electron transport in the succinate and formate oxidase systems. 4. In the anaerobic state, the endogenous ubiquinone was partly reduced by NADH or succinate. No increase in the reduction level of ubiquinone was found in the simultaneous presence of more than one hydrogen donor. 5. The results obtained suggest the presence of one ubiquinone pool which is located at the dehydrogenase site of cytochromeb.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00666077
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