Adenosylcobalamin-dependent methylmalonyl-CoA mutase isozymes in the photosynthetic protozoon Euglena gracilis Z.

The photosynthetic protozoon Euglena gracilis Z contains adenosylcobalamin-dependent methylmalonyl-CoA mutase (MCM) involved in propionate metabolism. The specific activity of the Euglena mutase was about 6.5-fold greater in propionate-adapted Euglena cells than in photoautotrophic cells and Food Science, (control). Although the control cells contained only one mutase (apparent M(r) 72 000), the propionate-adapted cells contained two mutases with M(r) values of 72 000 and 17 000; both enzymes were located in the mitochondria. These results provide evidence that propionate-adapted Euglena contains two MCM isozymes. The induced mutase (M(r) 17 000) permits photoassimilation of propionate.