The biosynthesis of n-[(2)H (7)] fatty acids byArthrobacter globiformis from [U-(2)H (15)] octanoic acid.

The principal fatty acids present whenArthrobacter globiformis is grown on a glycine medium free of normal fatty acids were found to be the C15 and C16 anteiso fatty acids; only a small amount of the normal fatty acids (C14 and C16) were present. Cells grown on the same medium but supplemented mented with 0.1 mg/ml [U-(2)H(15)]octanoic acid were found to contain an increased amount of the normal fatty acids and these fatty acids were found to be labeled with 7 deuteriums. I concluded that the octanoic acid is degraded by β-oxidation in these cells to [U-(2)H(7)] butyryl-CoA, which then competes with 2-methylbutyryl-CoA for the initiation of fatty acid biosynthesis.