Purification and Initial Characterization of Lipase from the Scutella of Corn Seedlings

Abstract

The lipase from the scutella of corn (Zea mays) MO-17 seedlings was purified 272-fold to apparent homogeneity as evidenced by sodium dodecyl sulfate polyacrylamide gel electrophoresis and double immunodiffusion. The procedure involved isolation of the lipid bodies, extraction with diethyl ether, DE-52 ion exchange chromatography, and sucrose density gradient centrifugation. The enzyme had an approximate molecular weight of 270,000 daltons after sucrose density gradient centrifugation, and 65,000 daltons after sodium dodecyl sulfate polyacrylamide gel electrophoresis. The lipase contained no cysteine and its molecular weight in sodium dodecyl sulfate was not reduced by beta-mercaptoethanol. The amino acid composition as well as a biphasic partition using Triton X-114 revealed the enzyme to be a hydrophobic protein. Rabbit gamma-globulin containing antibodies raised against the purified lipase formed one precipitin line with the lipase in a double diffusion test, and precipitated all the lipase activity from a solution.