Premium
Lipolytic activity of California‐laurel ( Umbellularia californica ) seeds
Author(s) -
Haas Michael J.,
Cichowicz David J.,
Dierov Jamil Kh.
Publication year - 2001
Publication title -
journal of the american oil chemists' society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.512
H-Index - 117
eISSN - 1558-9331
pISSN - 0003-021X
DOI - 10.1007/s11746-001-0390-0
Subject(s) - lauric acid , tripalmitin , lipase , germination , homogenization (climate) , glycerol , chemistry , chromatography , hydrolysis , fatty acid , triolein , glyceride , enzyme , triacylglycerol lipase , biochemistry , food science , biology , botany , biodiversity , ecology
The lipid content of dormant mature seeds of the California‐laurel ( Umbellularia califonnica ) was 74% (mass basis) and decreased upon germination, reaching 43% 5 wk after germination. Dormant seeds contained only barely detectable lipase activity. Lipase activity rose upon germination, peaking 2 to 3 wk after the onset of visible germination. The combined addition of three detergents, 3‐[(3‐cholamidopropyl)dimethylammonio]‐1‐propane‐sulfonate (1 mM), taurocholic acid (1 mM), and Tween‐20 (0.05%, vol/vol) during homogenization increased the lipolytic activity of total seedling homogenates by about 60%. Following centrifugation of homogenates from seedlings of various ages, ca. 80% of the recovered lipolytic activity was located in the fat‐free supernatant, with the remainder in the floating fat pad. The crude seed lipase did not show hydrolytic specificity for glycerol esters of lauric acid (the predominant fatty acid of the seed triglycerol): comparable lipolytic activities were seen toward olive oil, trilaurin, tripalmitin, and tristearin. Maximal lipolytic activity occurred at pH 8.5. This activity was stable over the pH range 6 to 9, and unstable at >40°C in a fashion that suggested the presence of multiple enzymes with different substrate specificities. Two lipolytic species, one of which showed some selectivity toward lauric acid esters, were partially separated from one another by ion‐exchange chromatography.