ISSN:
1573-6881
Keywords:
Oxidative phosphorylation
;
respiration
;
ATP
;
fluxes
;
Metabolic Control Analysis
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Chemistry and Pharmacology
,
Physics
Notes:
Abstract Strains carrying deletions in theatp genes, encoding the H+-ATPase, were unable to grow on nonfermentable substrates such as succinate, whereas with glucose as the substrate the growth rate of anatp deletion mutant was surprisingly high (some 75–80% of wild-type growth rate). The rate of glucose and oxygen consumption of these mutants was increased compared to the wild-type rates. In order to analyze the importance of the H+-ATPase at its physiological level, the cellular concentration of H+-ATPase was modulated around the wild-type level, using genetically manipulated strains. The control coefficient by the H+-ATPase with respect to growth rate and catabolic fluxes was measured. Control on growth rate was absent at the wild-type concentration of H+-ATPase, independent of whether the substrate for growth was glucose or succinate. Control by the H+-ATPase on the catabolic fluxes, including respiration, was negative at the wild-type H+-ATPase level. Moreover, the turnover number of the individual H+-ATPase enzymes increased as the H+-ATPase concentration was lowered. The negative control by the H+-ATPase on catabolism may thus be involved in a homeostatic control of ATP synthesis and, to some extent, explain the zero control by the H+-ATPase onE. coli growth rate.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02111653
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