SOLUBILIZATION AND PROPERTIES OF THE ENZYME-CLEAVING 13-L-HYDROPEROXYLINOLENIC ACID IN TEA LEAVES

Article abstract of DOI:10.1016/0031-9422(82)80005-8

The membrane bound hydroperoxide lyase (E₂'') which catalyses the cleavage of 13-L-hydroperoxides (18:3-OOH and 18:2-OOH) of linolenic and linoleic acids to C6-volatile aldehydes (hexenals and n-hexanal) was found to be localized in the chloroplast lamellae of tea leaves.It was selectively solubilized from the lamellae with 0.5percent (w/v) Tween 20.The enzymatic cleavage of the hydroperoxides occurred even under anaerobic conditions.The optimal pH of E₂'' was 7-8.The common structural features shown by substrates of E₂'' were the presence of a L-hydroperoxy group at ω-6 with a conjugated trans, cis-diene at ω-7 and ω-9 in a C18-fatty acid.E₂'' had an apparent K_m of 2.5 and 1.9 mM for 18:3-OOH and 18:2-OOH, respectively.No significant differences were found between chloroplast E₂'' and solubilized E₂''. - Key Word Index - Thea sinensis; Theaceae; tea; hydroperoxide lyase; hexenals; 13-L-hydroperoxylinolenic acid.