linoleic-acid and microcystin

Proteins of approximately 35, 55 and 65kDa were purified from cauliflower extracts by microcystin-Sepharose chromatography and identified by amino acid sequencing as plant forms of protein (serine/threonine) phosphatase 1 (PP1) catalytic subunit, PP5 and a regulatory A-subunit of PP2A, respectively. Peptides that corresponded both to the tetratricopeptide (TPR) repeat and catalytic domains of PP5 were identified. Similar to mammalian PP5,the casein phosphatase activity of plant PP5 was activated >10-fold by arachidonic acid, with half-maximal stimulation occurring at approximately 100 microM lipid.

Topics: Amino Acid Sequence; Arachidonic Acid; Chromatography, Affinity; Chromatography, Agarose; Chromatography, Ion Exchange; Enzyme Activation; Linoleic Acid; Microcystins; Molecular Sequence Data; Myristic Acid; Nuclear Proteins; Oleic Acid; Peptides, Cyclic; Phosphoprotein Phosphatases; Plant Proteins; Protein Phosphatase 1; Protein Phosphatase 2; Sequence Analysis