Abstract
1) The addition of amino acids, such as threonine, homoserine and methionine, to producing cultures resulted in an increase of the production of Corynecin II. α-Ketobutyric acid showed the similar effect.
2) The incorporation of these amino acids and the ketoacid into the propionyl group of Corynecin II was confirmed by the feeding experiments with labeled compounds, whereas propionic acid-U-14C was incorporated poorly into Corynecins with a relatively high degree of randomization of radioactivities.
3) L-Valine-U-14C was incorporated into Corynecin III, suggesting that the isobutyryl group of Corynecin III was derived from L-valine vi α-ketoisovalerate.
4) The origin of the acetyl group of Corynecin I was discussed on the basis of the incorporation experiments with acetate, pyruvate and L-alanine, all labeled with 14C.
