Increase in the phosphotransferase specific activity of purified Rous sarcoma virus pp60v-src protein after incubation with ATP plus Mg2+.
pp60v-src, the product of the Rous sarcoma virus src gene, was partially purified by immunoaffinity chromatography from extracts of Rous sarcoma virus-transformed field vole cells. Incubation of this preparation with ATP plus Mg2+ and subsequent repurification by chromatography on hexylamine-agarose resulted in a net increase in the specific activity of the src protein kinase. This increase in phosphotransferase activity was detected by using a variety of substrates including casein, tubulin, and a 34,000-dalton protein presumed to be an in vivo target substrate of pp60v-src. In all cases, the phosphorylation was at tyrosine residues, and the kinase activity was inhibited by preincubation of the enzyme with immunoglobulin G prepared from tumor-bearing rabbit sera. The implications of these results for the regulation and control of pp60v-src-associated kinase activity are discussed.
D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D001358:Avian Sarcoma Viruses / Q000378:metabolism*; D002364:Caseins; D002472:Cell Transformation, Viral; D007700:Kinetics; D008274:Magnesium / Q000494:pharmacology; D015688:Oncogene Protein pp60(v-src); D011494:Protein Kinases / Q000378:metabolism*; D014443:Tyrosine; D014764:Viral Proteins / Q000378:metabolism*
D002364:Caseins; D014764:Viral Proteins; D014443:Tyrosine; D000255:Adenosine Triphosphate; D011494:Protein Kinases; D015688:Oncogene Protein pp60(v-src); D008274:Magnesium