Esterase and lipase activity in Jatropha curcas L. seeds.
Two new esterases (JEA and JEB) and a lipase (JL) were extracted from the seeds of Jatropha curas L. Lipase activity was only found during germination of the seeds and increased to a maximum after 4 days of germination. All enzymes were found to be most active in the alkaline range at around pH 8 and the purified (fractionated precipitation with ethanol and gel filtration) esterases were very stable at high temperatures. The molecular weight (SDS-PAGE) of both esterases was determined to be 21.6-23.5 kDa (JEA) and 30.2 kDa (JEB) and the isoelectric point was 5.7-6.1 for esterase JEA and 9.0 for esterase JEB. Most ions caused a negative influence on the activity of both esterases. Using p-nitrophenyl butyrate as a substrate JEA showed a K(m) of 0.02 mM and a v(max) of 0.26 micromol mg(-1) min(-1). Under the same conditions JEB showed a K(m) of 0.07 mM and a v(max) of 0.24 micromol mg(-1) min(-1). Both esterases hydrolyzed tributyrin, nitrophenyl esters up to a chain length of =C4 and naphtylesters up to a chain length =C6. In transesterification reactions, JL was found to be most active at very low water activities (0.2) and in high water activities, the lipase hydrolysed triglycerides into conversions above 80%. The lipase hydrolysed both short chain and long chain triglycerides at about the same rate but was inactive on alpha-methylbenzyl acetate. JL is a potentially useful biocatalyst in the hydrolysis of triglycerides in organic solvents.
Staubmann
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R
Department of Biotechnology, Graz University of Technology, Graz, Austria.
Ncube
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Gübitz
G M
GM
Steiner
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Read
J S
JS
D004950:Esterases / Q000737:chemistry / Q000187:drug effects / Q000302:isolation & purification* / Q000378:metabolism; D006207:Half-Life; D006863:Hydrogen-Ion Concentration; D008049:Lipase / Q000302:isolation & purification* / Q000378:metabolism; D008670:Metals / Q000494:pharmacology; D009754:Nuts / Q000201:enzymology*; D012639:Seeds / Q000201:enzymology*; D013379:Substrate Specificity; D013696:Temperature
D008670:Metals; D004950:Esterases; D008049:Lipase