The basic amino-acid content of proteins

Abstract

A scheme of base-analysis is presented consisting of electrodialysis of a protein hydrolysate until free of nonbasic-N and detn. of arginine and histidine colorimetrically and lysine by N-difference. Analyses of reliable samples of 15 proteins of varied origin are presented. Casein, collagen, edestin, gelatin, gliadin, hemoglobin, insulin, [beta]-lactoglobulin, myosin, ovalbumin, salmine, silk fibroin, tobacco mosaic virus, wool keratin and zein contained, reported as % of the protein-N-arginine-N: 8.3, 15.2, 28.7, 15.3, 4.7, 7.2, 6.35, 5.9, 14.2, 11.7, 86.5, 1.9, 20.5, 20.2, 3 3; histidine-N: 5.5, 1.1, 4.2, 1.1, 3.2, 13.5, 8.55, 2.85, 3.9, 41, nil, 0.53, nil, 1.75, 2.2; lysine-N: 10.2, 4.7, 2.3, 4.9, 12, 9.8, 3.1, 13.6, 13.7, 7.4, nil, 0.7, 1.2, 3.1, nil, respectively. Collagen and gelatin also contain hydroxylysine-N at a level of 1.1-1.2% of the protein-N.