Purification and partial characterization of a membrane-associated lipoxygenase in tomato fruit.

摘要: Membrane-associated lipoxygenase from green tomato (Lycopersicon esculentum L. cv Caruso) fruit has been purified 49-fold to a specific activity of 8.3 μmol·min−1·mg−1 protein by solubilization microsomal membranes with Triton X-100, followed anion- exchange and size-exclusion chromatography. The apparent molecular mass the enzyme was estimated be 97 102 kD sodium dodecyl sulfate-polyacrylamide gel electrophoresis chromatography, respectively. membrane preparation consisted single major band following electrophoresis, which cross-reacts immunoserum raised against soluble soybean 1. It pH optimum 6.5, an Km 6.2 μm, Vmax 103. linoleic acid as substrate. Corresponding values for partially are 3.8 μm 1.3 protein, Thus, membrane-associated is kinetically distinguishable its counterpart. Sucrose density gradient fractionation isolated indicated that sediments thylakoids. A corresponding mol wt 97,000 identified immunologically in electrophoresis-resolved proteins thylakoids prepared intact chloroplasts leaves fruit.