Modification of kinetic parameters of glycogen phosphorylase from mantle tissue of Mytilus galloprovincialis by a phosphorylation mechanism
Initial rate and affinity studies on mantle Mytilus phosphorylase a were carried out in order to find possible differences in its kinetic properties with respect to phosphorylase b. Phosphorylase a was not stimulated for any AMP concentrations. Michaelis constants ( K m) are 0.05 mg/ml glycogen, 1.1...
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Published in | The international journal of biochemistry & cell biology Vol. 27; no. 9; pp. 917 - 922 |
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Main Authors | , , , |
Format | Journal Article |
Language | English |
Published |
Netherlands
Elsevier Ltd
01.09.1995
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Subjects | |
Online Access | Get full text |
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Summary: | Initial rate and affinity studies on mantle
Mytilus phosphorylase a were carried out in order to find possible differences in its kinetic properties with respect to phosphorylase b. Phosphorylase a was not stimulated for any AMP concentrations. Michaelis constants (
K
m) are 0.05 mg/ml glycogen, 1.15 mM inorganic phosphate and 1.50 mM glucose-1-phosphate. The
K
ms for the substrates, in the direction of glycogen breakdown, are enhanced by non-saturating concentrations of cosubstrate, without reducing the apparent maximum velocity. First order and hyperbolic kinetics and values of the allosteric constant smaller than 2 were observed. These results suggest a catalytic mechanism different to that shown for mantle
Mytilus phosphorylase b. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 1357-2725 1878-5875 |
DOI: | 10.1016/1357-2725(95)00059-X |