Characterization of a meso‐diaminopimelate‐sensitive aspartate kinase from cyanobacteria

A diaminopimelate‐sensitive aspartate kinase isozyme was identified in extracts of the cyanobacteria Anabaena PCC7120 and Synechococcus PCC7002 and purified 2800‐fold to homogeneity. The Mr of the enzyme was 110 000 and 55 000, respectively, under non‐denaturing and denaturing conditions, suggesting...

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Bibliographic Details
Published in:FEMS microbiology letters 1994-04, Vol.117 (3), p.257-262
Main Authors: Kochhar, S., Kochhar, V.K., Sane, P.V.
Format: Article
Language:English
Subjects:
Anabaena
Anabaena PCC7120
Aspartate kinase
Bacteriology
Biological and medical sciences
Cyanobacteria
Diaminopimelate
Freshwater
Fundamental and applied biological sciences. Psychology
Metabolism. Enzymes
Microbiology
Synechococcus
Synechococcus PCC7002
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Summary:A diaminopimelate‐sensitive aspartate kinase isozyme was identified in extracts of the cyanobacteria Anabaena PCC7120 and Synechococcus PCC7002 and purified 2800‐fold to homogeneity. The Mr of the enzyme was 110 000 and 55 000, respectively, under non‐denaturing and denaturing conditions, suggesting that the cyanobacterial diaminopimelate‐sensitive aspartokinase is a dimer composed of identical subunits. meso‐Diaminopimelate produced half‐maximal inhibition at 0.4 mM. Inhibition by 5 mM meso‐diaminopimelate varied between 50 and 80% with different enzyme preparations, probably owing to partial desensitization to allosteric inhibition. The diaminopimelate‐sensitive aspartate kinase described here is the first such isozyme reported outside the sporulating Gram‐positive genera Bacillus and Clostridium, and its possible function in cyanobacteria is discussed.
ISSN:0378-1097
1574-6968
DOI:10.1111/j.1574-6968.1994.tb06776.x