Turnover of the protein and carbohydrate moieties of a 105kD glycoprotein of plasma membranes from mouse liver determined by immunoprecipitation.

The turnover of a mouse liver plasma membrane glycoprotein (Mr 105 k) has been studied by means of immunoprecipitation and radioactive labeling. The method of immunoprecipitation proved to be a fast and efficient way of isolating a single protein for measurement of its specific radioactivity. The half-life of the carbohydrate moiety determined using 3H-galactose was 41 h and using 3H-mannose was 23 h, whereas that of the protein moiety determined using 3H-leucine was 63 h. The implications of this differential degradation of the protein and carbohydrate moieties are discussed in terms of the recycling of glycoproteins between the plasma membrane and intracellular membranes.