title: Role of plasma as activator and cofactor in phosphorylation catalyzed by protein kinase C.
abstract: The purpose of this study was to investigate whether plasma can influence the phosphorylation of protein kinase C (PKC). Lysate samples were prepared from normal skin or melanoma tissue and were reacted with a PKC peptide substrate in the presence or absence of plasma. In normal skin tissue lysates, the phosphorylation rates were much lower than those in melanoma tissue lysates. However, the level of phosphorylated peptide was increased in both normal skin and melanoma tissue lysates if plasma was present. Phosphorylation rates in the samples taken from the centre of B16 melanoma tissue were lower than those in samples taken from the edge. Moreover, addition of activator and/or cofactors (diacylglycerol, phosphatidylserine and/or Ca2+) of PKC, or plasma to the lysates contaminated by plasma had no effect on phosphorylation rates for the peptide substrate. These results indicate that plasma can play a role of activator and cofactor for substrate phosphorylation.
authors.affiliation: CREST, Japan Science and Technology Corporation, Kawaguchi-shi, Saitama, Japan.
authors.forename: Jeong-Hun
authors.initials: JH
authors.lastname: Kang
authors.forename: Daisuke
authors.initials: D
authors.lastname: Asai
authors.forename: Jun
authors.initials: J
authors.lastname: Oishi
authors.forename: Kenji
authors.initials: K
authors.lastname: Kawamura
authors.forename: Riki
authors.initials: R
authors.lastname: Toita
authors.forename: Yuhua
authors.initials: Y
authors.lastname: Jiang
authors.forename: Takeshi
authors.initials: T
authors.lastname: Mori
authors.forename: Takuro
authors.initials: T
authors.lastname: Niidome
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Katayama
mesh_terms: D000818:Animals; D002384:Catalysis; D003067:Coenzymes / Q000737:chemistry / Q000502:physiology*; D004789:Enzyme Activation / Q000502:physiology; D008297:Male; D008546:Melanoma, Experimental / Q000201:enzymology; D051379:Mice; D010455:Peptides / Q000138:chemical synthesis / Q000378:metabolism; D010766:Phosphorylation; D010949:Plasma / Q000737:chemistry / Q000502:physiology*; D011493:Protein Kinase C / Q000737:chemistry / Q000502:physiology*; D015398:Signal Transduction / Q000502:physiology; D012867:Skin / Q000201:enzymology; D013379:Substrate Specificity / Q000502:physiology
chemical_list: D003067:Coenzymes; D010455:Peptides; D011493:Protein Kinase C