[Enzymatic breakdown of linoleic acid hydroperoxides to volatile carbonyl compounds by isomerase from barley (author's transl)].
Barley protein fractions with active isomerase, purified by means of gelchromatography were incubated at room temperature with linoleic acid hydroperoxides (LHPO), containing 9-hydroperoxy-10-trans,12-cis-octadecadienoic acid (9-LHPO) and 13-hydroperoxy-9-cis,11-trans-octadecadienoic acid (13-LHPO) in the ratio of about 1:1. The volatile compounds resulting from the reaction have been isolated, concentrated and investigated by means of gas- and radio-gaschromatography. In the case of incomplete LHPO-breakdown remaining hydroperoxides and nonvolatile breakdown products have been separated before gaschromatographic analysis. In addition to hexanal as main product, traces of 2-tr-heptenal and 2-tr-octenal were found; about 6% of the converted hydroperoxides were transformed to carbonyl compounds. By numerous additional experiments it was confirmed that the volatile compounds are formed by enzymatic catalysis.
D001673:Biodegradation, Environmental; D002264:Carboxylic Acids; D002384:Catalysis; D002849:Chromatography, Gas; D002523:Edible Grain / Q000201:enzymology*; D001467:Hordeum / Q000201:enzymology*; D007202:Indicators and Reagents; D007535:Isomerases; D008041:Linoleic Acids; D008084:Lipoxygenase; D010545:Peroxides; D010940:Plant Proteins
D002264:Carboxylic Acids; D007202:Indicators and Reagents; D008041:Linoleic Acids; D010545:Peroxides; D010940:Plant Proteins; D008084:Lipoxygenase; D007535:Isomerases
Enzymatischer Abbau von Linolsäurehydroperoxiden zu flüchtigen Carbonylverbindungen durch Isomerase aus Gerste.