Concentration of Hydroperoxide Lyase Activities in Root of Cucumber Seedlings

Hydroperoxide lyases cleave hydroperoxide of linoleic and linolenic acid to form C6-aldehyde and/or C9-aldehyde. These enzymes are widespread in plants [1] but there exist various types of substrate specificity. HPO lyase solubilized from tea chloroplasts can act on 13-HPO but not on 9-HPO [2] and vice versa in the case of the enzyme partially purified from pear fruits [3], Extracts of Phaseolus vulgaris leaves can cleave both 9-HPO and 13-HPO [4], To elucidate the physiological role of these enzymes and products, i.e. C6and C9-aldehydes, we have been searching for suitable enzyme sources. In this way we found that extracts of cucumber seedlings could cleave both 9and 13-HPO at various efficiencies peculiar to each organ.