Alpha-ketoglutarate metabolism by cytochrome-containing anaerobes

During growth in the presence of tracer amounts of exogenously supplied alpha-keto[1-14C]glutarate (AKG) or alpha-keto [5-14C]glutarate, cytochrome-containing Bacteroides fragilis strain 2044 and Bacteroides vulgatus strain 8482 incorporated extremely small amounts of radioactivity into cell macromolecules and protoheme. Under identical conditions, Bacteroides "l" strain 7 CM and Bacteroides buccae strain J1 incorporated substantial label from [5-14C]AKG, but not [1-14C]AKG, into cellular macromolecules and protoheme. Bacteroides succinogenes strain S85 incorporated radioactivity from both [1-14C]AKG and [5-14C]AKG into cell macromolecules, but only label from [5-14C]AKG appeared in protoheme. Selenomonas ruminantium strain HD1 and Butyrivibrio fibrisolvens strain D1, both of which are devoid of cytochromes, incorporated substantial label from both [1-14C]AKG and [5-14C]AKG into cell macromolecules, but failed to incorporate label from either position into protoheme. Bacteroides ruminicola sp. brevis stra...