Purification of glucose transport proteins to use as analogues for injection into rabbits. The immunoproteins would be used for comparison of activity on proteins from normal and transformed cells. Separation of transport proteins by DEAE-cellulose column chromatography has given good resuts and should be repeated on a larger scale. Quantitation of glucose transport protein in fibroblasts with strongly stimulated glucose uptake due to glucose starvation should be compared with its increased presence and strong membrane binding in malignantly transformed cells. Suggestion of a link between glucose uptake stimulation and increased glycolysis in malignant cells makes it desirable to assay our uptake protein for an effect on glycolysis. The commercially available kit for enzymatic assay will be most convenient. Localization by electron microscopy of the pp60 src gene translation product in plasma membranes of RSV-transformed fibroblasts has been reported. Preliminary experiments using our further purified membrane preparations for assay of endogenous protein and phosphorylation products have been encouraging and will be continued. The qualitative differences between normal and RSV-transformed chicken fibroblasts and their membrane preparations, as well as similarity between transformed and normal glucose-starved cells we particuarly deem worth a more thorough exploration. The result, we hope, will help to clarify the role of our isolated transport factor as well as the general mechanism of metabolite transport.