The biosynthesis of glycoproteins. VI. Production of extracellular radioactive macromolecules by Ehrlich ascites carcinoma cells during incubation with glucosamine-14C.

The incorporation of glucosamine-'4C by Ehrlich ascites tumor cells has been mess ured both in vivo and in vitro. A considerable amount of high molecular weight radio active material appears outside of the cells under both conditions. The radioactive extracellular fluids were subjected to gel ifitration and to chromatography on DEAE cellulose (diethylaminoethyl cellulose) columns. These experiments demonstrated the presence of a number of labeled components differing in their affinity to DEAE cellulose, in their molecular size, and also in the ratio of 14C present as glucosamine and as galactosamine. Digestion with Pronase caused a considerable reduction of molecular sizes of the extracellular radioactive molecules, demonstrating that glyco protein-like molecules are present. The results suggested that a differential leakage of glycoproteins occurred both in vivo and in vitro.