ISOLATION AND PARTIAL CHARACTERIZATION OF A COTTON ROOT LIPASE

Crude extracts of cotton seedling roots (Gossypium hirsutum L. cv. Gua zuncho2) exhibit lipolytic activity on cottonseed oil. When the crude extract is centrifuged for 30 min at 4 degrees C and 11 000 g lipolyti c activity is recovered from the pellet by adding 20 mmol Tris-HCl buf fer (pH 8.5) containing 1% Triton X-100, 1 mmol DTT and 0.5 mmol EDTA. After centrifugation for 30 min at 50 000 g and for 1 h at 100.000 g the enzyme is recovered in the supernatant. The lipase shows maximum a ctivity at pH 8.0-8.5 and at 55 degrees C-65 degrees C and is stimulat ed by calcium. HPLC analysis of the remaining triacylglycerols (TAG) a fter the action of the lipase on cottonseed oil reveals higher affinit y for TAG containing oleic acid. Fractionation of the soluble enzyme p reparation by gel chromatography (Sephacryl S-300) shows the presence of two active fractions.