Use of trinitrobenzenesulfonic acid in the determination of protein amino groups on the external surface of rat erythrocyte membranes.

Description is provided of conditions selected for the study of protein amino groups (AG) on the external surface of rat erythrocyte membranes (EM) by means of 2,4,6-trinitrobenzenesulfonic acid (TNBS). The number of protein AG reacting with TNBS was influenced by the season of the year, the physiologic state of the donor animal, and other factors known to alter EM. It appears that structural perturbations introduced by these factors into EM are responsible for alterations in the accessibility of the protein AG to TNBS.