The incorporation of amino acid carbon by Rhodospirillum rubrum

Abstract

1. 1. Washed suspensions of Rhodospirillum rubrum incubated anaerobically in light incorporated carbon from L-glutamic acid and L-aspartic acid into all the cell fractions and all the protein amino acids examined. 2. 2. When the organism was grown exponentially on L-glutamic acid as major carbon and nitrogen source, 60% of the glutamic acid carbon was converted initially into carbon dioxide and an amount equivalent to approximately half of this was then assimilated by the organism. The remainder of the cell carbon was derived from glutamic acid by other mechanisms. 3. 3. In the synthesis of protein amino acids, carbon dioxide was utilized preferentially for alanine, serine and glycine. 4. 4. Studies with 14C- L-glutamic acid in the presence of other 12C-amino acids produced evidence for a biosynthetic relationship between glutamic acid and arginine and proline.