抄録
The ratio of the specific activity of glycine to that of serine isolated from soluble collagen of guinea pig skins, when radioactive glycine was injected intraperitoneally, was around 3-4. On the other hand, the specific activity ratio, Gly/Ser, in globin was around 8.
In the incubation experiments in vitro using minced skin from guinea pig fetuses with the aid of radioactive glycine as a tracer, the specific activity ratio, Gly/Ser, in collagen was around 4, agreeing closely with the data of the experiments in vivo. The same was observed in the biosynthesis of globin in vitro using bone marrow cells from guinea pigs, namely the specific activity ratios, Gly/Ser, were 9 to 12, being consistent with the data of the experiments in vivo.
The difference in the specific activity ratio, Gly/Ser, between collagen and globin way discussed from a viewpoint of specificity of the mode of complements of the two amino acids at the site of protein biosynthesis.
The authers wish to express our gratitude to Prof. Y. Ito for his encouragement, and to Dr. S. Ishibashi for his helpfull discussion. The authers are also indebted to Mr. H. Nishigori for his co-operation.
