RESEARCH ARTICLE

Journal of Oil Palm Research (Special Issue), p. 54-63

GLYCEROL-3-PHOSPHATE ACYLTRANSFERASE REACTIONS AND EDIBLE OIL IN SYNTHESIS IN OIL PALM (Elaeis guineensis) TISSUE

MOHD ARIF, A M*; HARWOOD, J L**

ABSTRACT

Acyltransferase enzymes are used in three of the four steps of the Kennedy pathway for storage lipid formation. Their specifities, especially those of the first two reactions involving glycerol-3-phosphate acyltransferase (GPAT) and 1-acylglycerol-3-phosphate acyltransferase (LPAAT), determine the acyl quality of triacylglycerol (TAG) to a significant extent. Therefore, we determined the characteristics of the acyltransferases in oil palm (Elaeis guineensis), one of the world’s most important agricultural species and the most productive oil crop. Two tissue sources were used. Calli were established and used for in situmanipulation and labelling studies as well as a source of microsomal fractions for enzyme measurements. In addition, acetone powder was prepared from oil palm fruits (14-18 weeks after pollination) for enzyme purification. High speed particulate fractions isolated from mesocarp acetone powder or calli were incubated with [14C]glycerol 3-phosphate and the formation of Kennedy pathway intermediates followed. Conditions were optimized with regard to substrate concentrations, etc. and the overall rate manipulated using temperature. GPAT was solubilized from particulate fractions of the acetone powder and calli. Optimal solubilization of GPAT activity using CHAPS treatment was achieved at 0.5% (wlv) concen-tration. Details of the purification procedure and properties of the solubilized enzyme are discussed.

KEYWORDS:


* Palm Oil Research Institute of Malaysia,
P.O. Box 10620, 50720 Kuala Lumpur, Malaysia.

** Cardiff School of Bioscences,
Cardiff University, P.O. Box 911,
Cardiff CF1 3US, U.K.