| Abstract: | Murine LSTRA lymphoma cells contain a very active tyrosine protein kinase of 56 kDa (p56) which is not related to any of the other known tyrosine kinases. In the past the purification and characterization of the p56 have been hampered because of the low amount of this protein in LSTRA membranes. In this study, we have utilized a different approach for purification which consisted of trapping the protein in the membrane of vesicular stomatitis virus. Incubation of the virions with gamma-32P]ATP resulted in the phosphorylation of p56 on tyrosine residues. Moreover, the phosphopeptide digest profile of vesicular stomatitis virus-p56 was identical to that observed with authentic LSTRA-p56. The p56 from such virions could be resolved from other proteins by two-dimensional gels, and furthermore, such virions have been used to prepare several antisera directed against the p56. |
