Purification and Characterization of Lipolytic Acyl-hydrolases from Rice Bran

Rice bran lipase, phospholipase and galactolipase were extracted, purified and thenn characterized as the enzyme mixtures. All the enzymes were eluted on Sephadex G-100, column as one peak, showing that they have a similar molecular weight around 40,000. On DEAE-Sephadex A-50 column, these enzymes were further separated into two to four components, respectively. Chemical modification suggests that serine, cystine or cysteine group was involved in the enzyme activities. The galactolipase and phospholipase exhibited hydrolytic activities for both monoand diacyl lipids. The galactolipase preferentially hydrolyzed the fatty acid esters at 1-position of galactolipids and the lipase those at 1,3 positions of triglycerides, but the phospholipase did not show such a specificity at a significant rate. The lipid degradation in rice bran during rice storage was also discussed in relation with the properties of the rice bran enzymes. (Received May 19, 1975)