Carbohydrate composition of sarcolemma of rat myocardium

The carbohydrate composition of SL prepared from rat ventricular muscle was examined and compared with those of Mw and FSR prepared from the same species. The total carbohydrate content of SL was 308.58 micrograms/mg of protein, which was greater than that of Mw (74.49 micrograms/mg of protein) and FSR (76.50 micrograms/mg of protein). The carbohydrate of SL was composed of hexose (35.0%), hexuronic acid (7.3%), sialic acid (6.1%), methyl pentose (7.4%), and hexosamine (44.2%). The peculiar PAS-positive glycoproteins of SL were observed as five bands on polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate and the molecular weight of the main band of these was 85.4 kDa. Thus, each of the cell fractions obviously shows a distinct carbohydrate composition and the results obtained in the present study may suggest that the presence of the PAS-positive glycoprotein (85.4 kDa) can be used for routine monitoring of the purity of the SL fraction.