Cloning and expression of a lipase gene from rice (Oryza sativa cv. Dongjin)

Lipases are useful enzymes that are primarily responsible for the hydrolysis of acylglycerides during lipid processing. We have cloned a lipase gene from a rice seed coat cDNA library (Oryza sativa cv. Dongjin). The cDNA was 1,445 bp in length and encoded 361 amino acid residues (GenBank accession No. AY580163). The deduced amino acid sequence had 82 and 56% identity to Oryza sativa (cv. Chuchung) and Arabidopsis thaliana lipase genes, respectively, and there was a GxSxG consensus motif near the catalytic triad at the active serine site. The deduced sequence had little homology to mammalian and microbial lipases. When the Oryza sativa lipase gene was expressed in Escherichia coli with the pET expression system, activity was found mainly in the pellet fraction. The purified product had lipolytic activity towards tributyrin and was about 40 kDa in size.