Regulation of spinach-leaf nitrate reductase by reversible phosphorylation.
Okadaic acid and microcystin (but not the inactive methyl esters of these toxins) prevented the rapid light-induced activation of nitrate reductase (NR) in intact spinach leaves. In vitro, nitrate reductase was inactivated by a protein kinase and activated by PP2A. The role of reversible protein phosphorylation in regulation of light-coupled cytoplasmic metabolism is discussed.
MacKintosh
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Department of Biochemistry, University of Dundee, UK.
D004789:Enzyme Activation; D004988:Ethers, Cyclic / Q000494:pharmacology; D008027:Light; D008387:Marine Toxins; D052998:Microcystins; D050901:Nitrate Reductase; D009565:Nitrate Reductases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D019319:Okadaic Acid; D010456:Peptides, Cyclic / Q000494:pharmacology; D010749:Phosphoprotein Phosphatases / Q000037:antagonists & inhibitors / Q000378:metabolism; D010766:Phosphorylation; D010944:Plants / Q000201:enzymology*
D004988:Ethers, Cyclic; D008387:Marine Toxins; D052998:Microcystins; D010456:Peptides, Cyclic; D019319:Okadaic Acid; D009565:Nitrate Reductases; D050901:Nitrate Reductase; D010749:Phosphoprotein Phosphatases; C057862:cyanoginosin LR