Vitamin B12 dependent glutamate mutase activity in photosynthetic bacteria

Summary Cell-free extracts of Rhodopseudomonas spheroides and Rhodospirillum rubrum grown photosynthetically on Co 2+ -supplemented media converted glutamate to β-methylaspartate and further deaminated the latter to form mesaconate. The conversion was inhibited by hog intrinsic factor and the inhibition was restored by coenzyme B 12 . The catalytic activity of cell-free extracts from the cells grown on Co 2+ -deficient media was extremely low and enhanced markedly by the addition of coenzyme B 12 to the reaction system.