Purification and characterization of an intracellular lipase from pleopods of whiteleg shrimp (Litopenaeus vannamei)

An intracellular lipase present in the whiteleg shrimp Litopenaeus vannamei was detected in pleopods. The lipase from pleopods was purified and characterized by biochemical and kinetic parameters. Purified intracellular lipase has a molecular mass of 196 kDa, the polypeptide is assembled by two monomers, 95.26 and 63.36 kDa. The enzyme lacks glycosylation, and it has an isoelectric point of 5.0. The enzyme showed the highest activity at a temperature range of 30-40 degrees C at pH 8.0-10.0. Activity was completely inhibited by tetrahydrolipstatin and diethyl p-nitrophenyl phosphate, suggesting that the intracellular lipase is a serine lipase. The lipase hydrolyzes short and long-chain triacylglycerides, as well as naphthol derivatives at comparable rates in contrast to other sources of lipases. Specific activity of 930 U mg(-1) and 416.56 U mg(-1) was measured using triolein and tristearin at pH 8.0 at 30 degrees C as substrates, respectively. The lipase showed a K-M.app of 41.03 mM and k(cat)/K-M.app ratio of 4.88 using MUF-butyrate as the substrate. The intracellular lipase described for shrimp has a potential role in hydrolysis of triacylglycerides stored as fat body, as has been shown in humans. (C) 2010 Elsevier Inc. All rights reserved.