High level expression and characterization of a thermostable lysophospholipase from Thermococcus kodakarensis KOD1

초록

Phospholipases can catalyze the hydrolysis of one or more ester and phosphodiester bonds and have a considerable interest in the food, oil leather and pharmaceutical industries. In this report, a lysophospholipase gene from the hyperthermophilic archaeon Thermococcus kodakarensis KOD1 (LysoPL-tk) was cloned. The gene of 783 bp encodes a 260-amino acid protein with a molecular mass of 29 kDa. LysoPL-tk has a consensus motif (GxSxG) and a catalytic triad (S, D, H) of esterases in the deduced amino acid sequence. LysoPL-tk was expressed in Escherichia coli and purified to homogeneity. The enzyme can degrade substrates with both short and long acyl chain lengths. The apparent K (m) value for p-nitrophenyl butyrate was 607.1 mu M with V (max) values of 95.5 U/mg. The enzyme was active at a broad range of pH (5-8) and temperatures (70-95 A degrees C) with the optimum pH and temperature being 8.0 and 85 A degrees C, respectively. The high yield, broad substrate range along with its thermo-stability indicates that LysoPL-tk is a potential enzyme in industrial application.

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