Abstract
1. Nearly all sorts of protein give arginine value about one third to that of its hydrolysate. This means that two third of arginine mole-cules in protein enters into combination of its guanidine group.
2. The guanidine linkage of arginine in protein molecule is easily splitted by mild treatment of acid.
3. The arginine molecule bound in peptide chain can give the full colour reaction, if its guanidine group is free.
In conclusion the author wishes to express my hearty thanks to Prof. Emeer. S. Kakiuchi and Prof. K. Kodama for their kind advice.
