I1 hvH2-CH2-C-CHzCOOH I ber of ways. Possible biosynthetic pathways leading to the formation of I would include the condensation of the Coenzyme X derivatives of glycine and acetic acid, the condensation of malonyl Co-eiizyine A and glycine (with concomitant loss of COL from the glycine carboxyl), the reductive aniination of oxaloacetic semialdehyde or finally, through a fatty acid-like oxidation of y-aminobutyric acid.