The Effect of pH on the Sorption of Collagen-Derived Peptides by Hair

Synopsis--Sorption of peptides increases very rapidly during the first few minutes to one-half hour of peroxide or thioglycolate treatment, after which sorption is essentially constant for a period, increasing rapidly again as the hair is damaged more extensively. The conclusion is drawn that the first action is on the cuticle which is readily removed by chemical treatment, and that increased sorption occurs after removal of the cuticle, only after extensive damage to the cortex. Oxidizing agents cause a maximum sorption of peptide at neutral pH values, while thioglycolate causes maximum sorption at high pH levels. Sorption appears to be an equilibrium phenomenon governed by the pH value of the peptide solution.