PROPIONYL-COA CARBOXYLASE OF MYXOCOCCUS-XANTHUS - CATALYTIC PROPERTIES AND FUNCTION IN DEVELOPING CELLS

Citation
Y. Kimura et al., PROPIONYL-COA CARBOXYLASE OF MYXOCOCCUS-XANTHUS - CATALYTIC PROPERTIES AND FUNCTION IN DEVELOPING CELLS, Archives of microbiology, 170(3), 1998, pp. 179-184
Citations number
31
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Microbiology
Journal title
ISSN journal
0302-8933
Volume
170
Issue
3
Year of publication
1998
Pages
179 - 184
Database
ISI
SICI code
0302-8933(1998)170:3<179:PCOM-C>2.0.ZU;2-M
Abstract
An acyl-coenzyme A carboxylase that carboxylates acetyl-CoA, butyryl-C oA, propionyl-CoA, and succinyl-CoA was purified from Myxococcus xanth us. Since the enzyme showed maximal rates of carboxylation with propio nyl-CoA, the enzyme is thought to be propionyl-CoA carboxylase. The ap parent K-m values for acetyl-CoA, butyryl-CoA, propionyl-CoA, and succ inyl-CoA were found to be 0.2, 0.2, 0.03, and 1.0 mM, respectively. Th e native enzyme has a molecular mass of 605-615 kDa and is composed of nonidentical subunits (alpha and beta) with molecular masses of 53 an d 56 kDa, respectively. The enzyme showed maximal activity at pH 7.0-7 .5 and at 25-30 degrees C, and was affected by variation in concentrat ions of ATP and Mg2+. During development of M. xanthus, the propionyl- CoA carboxylase activity increased gradually, with maximum activity ob served during the sporulation stage. Previous work has shown that a pr opionyl-CoA-carboxylase-deficient mutant of M. xanthus reduces levels of long-chain fatty acids. These results suggest that the propionyl Co A carboxylase is also responsible for the carboxylation of acetyl-CoA to malonyl-CoA used for the synthesis of long-chain fatty acids during development.