Identification of a 58,000 Daltons phosphoprotein with tyrosine protein kinase activity in a murine lymphoma cell line

摘要: A very high level of tyrosine protein kinase (TPK) activity has been recently detected in a murine lymphoma, induced by Moloney leukemia virus. major endogenous substrate for phosphorylation vitro is Mr 55–60,000 (p58) associated with the detergent insoluble matrix LSTRA cells ; present work p58 was solubilized, isolated anion exchange chromatography and then precipitated antiphosphotyrosine antibodies. Through these steps isolation, TPK measured use simplified gastrin assay. It demonstrated that copurifies p58, which leads to conclusion bears itself enzymatic activity. Although functionnally similar other enzymes this group, newly characterized does not seem be closely related one previously documented TPK. This suggests either product so far unrecognized cellular gene or it derives from rearrangement described genes.