FATTY-ACID HYDROPEROXIDE CLEAVING ENZYME, HYDROPEROXIDE LYASE, FROM TEA LEAVES

Hydroperoxide cleaving enzyme, hydroperoxide lyase (HPO lyase), was firstly purified to homogeneity from membranous fraction of tea leaves. The enzyme was separated with hydroxyl apatite gel chromatography into two fractions, HPO lyase I and II having M(r) of 55 000 and 53 000, respectively. Almost the same pH-activity profiles were obtained with these two forms of HPO lyases. Antioxidants which are known as potent inhibitors for lipoxygenase such as nor-dihydroguaiaretic acid and butylated hydroxyanisole inhibited the activity of HPO lyase I. Activity for 13-hydroperoxide of alpha-linolenic acid was ca 10 times higher than that for 13-hydroperoxide of linoleic acid but the positional isomer, 13-hydroperoxide of gamma-linolenic acid was a relatively poor substrate.