%0 Journal Article %A Pearce, J. %A Leach, C. K. %A Carr, N. G. %T The Incomplete Tricarboxylic Acid Cycle in the Blue-green Alga Anabaena Variabilis %D 1969 %J Microbiology, %V 55 %N 3 %P 371-378 %@ 1465-2080 %R https://doi.org/10.1099/00221287-55-3-371 %I Microbiology Society, %X Summary: The presence of an incomplete tricarboxylic acid cycle in Anabaena varia-bilis and Anacystis nidulam is described. These blue-green algae lack both α-oxoglutarate dehydrogenase and succinyl-CoA synthetase. Succinyl-CoA was formed in extracts of A. variabilis by 3-ketoacyl CoA-transferase using acetoacetyl-CoA as CoA donor. The activities of the other tricarboxylic cycle enzymes were measured in extracts prepared from autotrophic organisms and from those grown in the presence of acetate. No alterations in activity indicative of enzyme repression or de-repression were observed. These results are discussed in relation to possible reasons for autotrophic behaviour. %U https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-55-3-371