Studies on the reactive groups of collagen. I. Acylation and guanidino group destruction

Abstract

1. 1. Collagen was benzoylated with benzoyl chloride or benzoic anhydride under several conditions. The maximum amount of benzoyl groups introduced was only 0.7 mmoles/g. collagen. 2. 2. It has been shown that the benzoyl groups are attached to the amino and guanidino groups of collagen. 3. 3. Methods for quantitative as well as for selective acetylation of collagen were developed. The quantitative acetylation of all the amino and hydroxyl groups of collagen was effected. The maximum amount of acetyl groups introduced was 2.1 mmoles/g. collagen. 4. 4. About 50% of the hydroxyl groups of collagen were acetylated selectively without materially affecting the amino groups by means of acetic anhydride in the presence of thiocyanic acid. 5. 5. All the free amino groups and only a small portion of the hydroxyl groups were involved in the acetylation of collagen with acetyl pyridinium chloride. 6. 6. The transesterification method for the quantitative estimation of total acetyl groups was standardized. 7. 7. About 70% of arginine and about 17% of histidine in collagen were destroyed by treatment with sodium hypobromite.