Purification and characterization of lipase enzyme from cotton seed (Gossypium hirsutum L.)

Lipases are known as enzymes that the provide hydrolysis of esters, which ocur glycerol and fatty acids. The importance, role and the uses in the biological processes of lipases are increasing day by day. In this study it was aimed that purification and characterization of lipases from cotton seed. Thus an alternative to lipase enzyme used in the industry were obtained. For this reason the methods mentioned below were applied respectively. Defatting of seeds, ammonium sulfate precipitation, dialysis, gel filtration chromatography etc. In all purification steps protein quantity was measured according to Bradford method and lipase activity was measured by titrimetric method. Specific activity was calculated and it was determined that lipase was purified 35.2 fold. To determine molecular weight of cotton seed lipase SDS-PAGE was performed and the molecular weight was identified as 21 kDa. Maximum acitivity of cotton seed lipase was observed at pH 10.4 and 50 ˚C. It was found that stabil pH and stabil temperature 10.0 and 60 ˚C, respectively. To determine storage stability of purified lipase, activities were measured for two weeks. After two weeks lipases in 4 ˚C were protect their catalytic activity. To calculate Km and Vmax of cotton seed lipase, triolein was used substrate and Km and Vmax values were found that 17.5178 mM and 9.5192 U/min.mg enzyme, respectively. Key Words: Cotton seed, lipase, purification, characterization.