Changes in NADP-isocitrate dehydrogenase isoenzyme levels inAcinetobacter calcoaceticusin response to acetate

During adaptation of Acinetobacter calcoaceticus to growth on acetate the specific activity of NADP-isocitrate dehydrogenase increased. This response is unique, as in other bacteria grown under the same conditions the activity of the enzyme decreases as a result of covalent phosphorylation. Moreover, A. calcoaceticus is also unusual in containing two distinct isoenzymes of NADP-isocitrate dehydrogenase. It has here been shown that the adaptation of A. calcoaceticus to acetate is accompanied by an increase in the relative proportion of the larger, allosteric, isoenzyme with a concomitant decrease in the level of the smaller, non-allosteric, isoenzyme.