title: [On lipoxygenase and enzymes which decompose linoleic acid hydroperoxides in rye (author's transl)].
abstract: An enzyme fraction from rye containing lipoxygenase activity was investigated. The molecular weight of lipoxygenase was found to be about 102000. Two bands groups with isoelectric points between 5.1-5.5 and 5.8-6.4 were obtained by isoelectric focusing. Three isoenzymes could be separated by ion exchange chromatography. Lipoxygenase has optimum activity at pH 7.3-7.5 and predominantly forms 13-hydroperoxy-9-cis, 11-trans-octadecadienoic acid (13-LHPO). In rye the 13-LHPO is converted to alpha-ketols by a high molecular protein fraction. This isomerase converts the LHPO formed by rye lipoxygenase predominantly to 12,13-ketohydroxy acids. The Michaelis Constant of isomerase is 3-5 X 10(-5), using LHPO as substrate. At low protein concentrations the reaction velocity of LHPO-conversion increases linearly with protein concentration.
mesh_terms: D007700:Kinetics; D008084:Lipoxygenase / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D008970:Molecular Weight; D010544:Peroxidases / Q000378:metabolism*; D010944:Plants / Q000201:enzymology*; D012434:Secale / Q000201:enzymology
chemical_list: D010544:Peroxidases; D008084:Lipoxygenase
vernacular_title: Uber Lipoxygenase und Linolsäurehydroperoxid-abbauende enzyme in Roggen.