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Glucose Metabolism in 6-Phosphogluconolactonase Mutants of Escherichia coli
Absence of 6-phosphogluconolactonase alone slightly decreases the growth rate of Escherichia coli on glucose. In such a strain there is considerable, and possibly normal, use of the oxidative hexose monophosphate shunt, according to ribose specific activity after growth on [1- 14 C]glucose. Thus, ab...
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Published in: | The Journal of biological chemistry 1972-03, Vol.247 (6), p.1904-1910 |
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Main Authors: | , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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Summary: | Absence of 6-phosphogluconolactonase alone slightly decreases the growth rate of Escherichia coli on glucose. In such a strain there is considerable, and possibly normal, use of the oxidative hexose monophosphate shunt,
according to ribose specific activity after growth on [1- 14 C]glucose. Thus, absence of lactonase, even in a strain with genetic deletion of lactonase, does not block the shunt.
A strain which lacks both phosphoglucose isomerase and glucose 6-phosphate dehydrogenase does not grow at all on glucose.
A strain lacking isomerase and lactonase, however, does grow very slowly on glucose. Thus the shunt can function as the sole
pathway of glucose metabolism in a lactonase mutant.
Metabolism of 6-phosphogluconolactone past the enzyme block of the mutant probably occurs mainly by spontaneous hydrolysis,
giving the normal product, gluconate 6-phosphate. However, some metabolism uses a new sequence of reactions bypassing the
lactonase: dephosphorylation and excretion of gluconolactone, hydrolysis of the gluconolactone in the medium, and uptake and
phosphorylation of the gluconic acid. |
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ISSN: | 0021-9258 1083-351X |
DOI: | 10.1016/S0021-9258(19)45556-7 |