Purification and characterization of proteins with associated tyrosine protein kinase activity from human B lymphocytes.

Burkitt lymphoma cells and their counterpart of normal origin contain proteins with associated tyrosine protein, kinase activity. These proteins were isolated by affinity chromatography and Fast Pressure Liquid Chromatography. Proteins with enzyme activity had an app. M. W. of 47 KDa. This protein in extracts of Burkitt lymphoma cells differed by overall charge and phosphorylation from the 47 KDa protein isolated from B lymphocytes of normal origin. Before and after purification the 47 KDa protein of Burkitt lymphoma cells reacted with an antibody directed against the dodecapeptide Arg-Arg-Leu-Ile-Glu-Asp-Asn-Glu-Tyr-Thr-Ala-Arg (conserved region of pp60src), the 47 KDa protein from B cells of normal origin did not; the same protein from both cell lines reacted with anti-pp60src antibody. These results suggest that a tyrosine protein kinase, related to the products of the src family of oncogenes, is modified in Burkitt lymphoma cells.