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Two separate tyrosine protein kinases in human platelets
Author(s) -
Nakamura Shun-ichi,
Takeuchi Fumito,
Tomizawa Tamami,
Takasaki Noriko,
Kondo Hiroki,
Yamamura Hirohei
Publication year - 1985
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(85)80652-9
Subject(s) - cytosol , biochemistry , tyrosine , divalent , chemistry , platelet , substrate (aquarium) , kinase , peptide , tyrosine kinase , protein tyrosine phosphatase , enzyme , biology , signal transduction , immunology , ecology , organic chemistry
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, E 11 G 1 , (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 M r 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.