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Protein kinase C of a human megakaryoblastic leukemic cell line (MEG‐01) Analysis of subspecies and activation by diacylglycerol and free fatty acids
Author(s) -
Kitagawa Yasuo,
Matsuo Yoshinobu,
Minowada Jun,
Nishizuka Yasutomi
Publication year - 1991
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(91)80998-i
Subject(s) - diacylglycerol kinase , protein kinase c , biochemistry , arachidonic acid , chemistry , phosphatidylserine , enzyme , oleic acid , linoleic acid , diglyceride , protein kinase a , biology , fatty acid , phospholipid , membrane
Protein kinase C (PKC) from a human megakaryoblastic leukemic cell line (MEG‐01) was resolved into two fractions by hydroxyapatite column chromatography, which are indistinguishable from the brain type II (βI/βII) and type III (α) subspecies, by biochemical and immunoblot analysis. In the presence of both phosphatidylserine and diacylglycerol, several free unsaturated fatty acids (FFA's), such as arachidonic, oleic, linoleic and linolenic acids, further enhanced the enzyme activation, and allowed the enzyme to exhibit almost full activity at nearly basal levels of Ca 2+ concentration. The concentration of unsaturated FFA's giving rise to the maximum enzyme activation was around 2 × 10 −5 M. Palmitic and stearic acids were inactive. The result implies that, in addition to diacylglycerol, the receptor‐mediated release of unsaturated FFA's from membrane phospholipids may also take part in the activation of PKC.