title: [Increase, in extracts of cancerous or transformed cells, of protein kinase activity phosphorylating tyrosine].
abstract: A protein kinase activity which phosphorylates tyrosine in the presence of Mn++ ions has been detected among different protein kinase activities in a postnuclear cell fraction sedimenting mostly at 12000 X g. The proportion of phosphotyrosine relative to phosphoserine and phosphothreonine is at a low level in normal embryonic cultured cells and is increased several fold in various types of cells either malignant or transformed in vitro. This proportion which may reach up to 8% is in the same range as that found in extracts of avian cells transformed by Rous sarcoma virus, where the viral kinase P60 src is expressed. In two ascitic tumour cells the tyrosine kinase activity seems to be associated with the mitochondrial fraction.
mesh_terms: D000596:Amino Acids / Q000032:analysis; D000818:Animals; D001358:Avian Sarcoma Viruses / Q000235:genetics; D002471:Cell Transformation, Neoplastic; D002642:Chick Embryo; D004625:Embryo, Nonmammalian; D006801:Humans; D007700:Kinetics; D007939:Leukemia L1210 / Q000201:enzymology*; D051379:Mice; D010766:Phosphorylation; D011494:Protein Kinases / Q000378:metabolism*; D011784:Quail; D012510:Sarcoma 180 / Q000201:enzymology*; D014443:Tyrosine / Q000378:metabolism*
chemical_list: D000596:Amino Acids; D014443:Tyrosine; D011494:Protein Kinases
vernacular_title: Augmentation, dans des extraits de cellules cancéreuses ou transformées, de l'activité d'une protéine-kinase phosphorylant la tyrosine.