Some characteristics of the residue obtained after pronase treatment of sheep erythrocyte membranes. II. Carbohydrate patterns.

The composition of single carbohydrate classes of intact and pronase treated sheep erythrocyte membranes has been studied. In comparison with the data obtained from untreated stromata after proteolytic digestion the amount of each class of sugars is decreased. A high disappearance of sialic acids and hexosamines can be observed. Nevertheless if the total sugar content is referred to the residual protein content (16% of the native proteins, an enrichment in carbohydrates, specially neutral hexoses, can be observed. The results indicate that most of the carbohydrate fractions solubilized by pronase treatment are sialic acids and hexosamines. Different molar ratios obtained for the single carbohydrate classes in comparison with NANA before and after pronase treatment suggest a microheterogeneity of the glycoprotein structure of sheep erythrocyte membranes. By the use of several analytical methods the residue obtained after pronase treatment shows two major fractions containing proteins, lipids and carbohydrates. The data are discussed in view of the possible arrangement of lipo-glycoproteins in sheep erythrocyte membrane.