Contributions to silkworm biochemistry VIII. — Conversion of pyruvate into alanine glycine and serine of silkfibroin

Abstract

When pyruvate-1-C was given per os to silkworms, C14 appeared in C-1 in the alanine, serine and glycine isolated from the cocoon. When pyruvate-2-C14 or 3-C14 was given, the activity appeared in all positions in alanine, serine and glycine. The specific activity was highest in alanine and it must be even higher in the fibroin of the section of the silkthread synthesized immediately after the pyruvate was fed. In the 3 experiments, about 9% of the ingested pyruvate was converted into alanine of silkfibroin. In spite of the failure to find pyruvate in the body fluid or in the silkglands of Bombyx mori, the alanine, and to a minor extent, the glycine and the serine incorporated in the silkworm can be derived from all sources leading to pyruvate in the metabolism of the silkworm.