CHARACTERIZATION OF PROTEIN-KINASE-C IN XENOPUS OOCYTES

Protein kinase C (PKC) was partially purified from Xenopus laevis oocytes by ammonium sulfate fractionation followed by DEAE-cellulose and hydroxyapatite column chromatography. In the latter chromatography, two distinct PKC activities were identified. Both PKC fractions contained an 80 kDa protein which was recognized by three antisera raised against the conserved regions of mammalian PKC. However, specific antisera against α, βI, βII, and γ-subspecies of rat PKC did not recognize the protein. Kinetic properties of the Xenopus PKCs were very similar to those of the rat αPKC, and only a subtle difference was found in the mode of activation by arachidonic acid. When oocytes were treated with the tumor promoter, phorbol 12-myristate, 13-acetate, one of the Xenopus PKCs was found to disappear very rapidly, while the other remained unchanged up to 2 hr. © 1992 Academic Press, Inc.