title: Two separate tyrosine protein kinases in human platelets.
abstract: Tyrosine protein kinase activities were detected in the cytosolic fraction (PC-TPK) and the particulate fraction (PM-TPK) in human platelets using the synthetic peptide, E11G1 (Glu-Asp-Ala-Glu-Tyr-Ala-Ala-Arg-Arg-Arg-Gly) as a substrate. PC-TPK and PM-TPK were different in substrate specificities, divalent cation requirements and apparent Mr values. These results strongly suggest that in platelets there exist at least two separate tyrosine protein kinases; one is present in cytosol and the other might be associated with membranes.
mesh_terms: D001792:Blood Platelets / Q000201:enzymology*; D003600:Cytosol / Q000201:enzymology; D006801:Humans; D008970:Molecular Weight; D011494:Protein Kinases / Q000097:blood*; D011505:Protein-Tyrosine Kinases
chemical_list: D011494:Protein Kinases; D011505:Protein-Tyrosine Kinases