ISSN:
1573-4927
Keywords:
Drosophila melanogaster
;
glutamine synthetase isozymes
;
structural comparison
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Chemistry and Pharmacology
Notes:
Abstract Glutamine synthetase II was purified from Drosophila melanogaster adults. It was completely separable from the isozyme glutamine synthetase I by means of DEAE chromatography. The complete enzyme has an apparent molecular weight of 360,000. After two-dimensional electrophoresis it gave a single molecular species with an apparent molecular weight of 42,000. Structural analysis of the two isozymes showed that they are different both in subunit molecular weight and in isoelectric point. Peptide maps of the purified subunits showed considerable dissimilarity. Glutamine synthetase II is more active than glutamine synthetase I in the transferase assay, while the opposite is true in the biosynthetic assay. The kinetic parameters were determined, showing again noteworthy differences between the two isozymes. We therefore conclude that two forms of glutamine synthetase are present in Drosophila, with different primary structures, different kinetic behavior, and the possibility of different functional properties.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00502602
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