Stimulation of microsomal diacylglycerol acyltransferase activity from microspore-derived cell suspension cultures of oilseed rape

Several factors including an unidentified endogenous substance were found to stimulate microsomal diacylglycerol acyltransferase (DGAT, EC 2.3.1.20) from a microspore-derived cell suspension culture of oilseed rape (Brassica napus L. cv Jet Neuf). Mg2+ salts were found to stimulate microsomal DGAT 14 to 23-fold. ATP and CoA were also found to stimulate the enzyme 2.4 and 12 fold respectively, although the effects were decreased in the presence of high Mg2+ concentrations. While microsomal DGAT activity was only slightly increased by the concentration of exogenous diacylglycerol in the reaction mixture it was increased substantially by the addition of exogenous phosphatidate. Other phospholipids tested were not found to have this stimulatory effect. During attempts to investigate possible covalent modification of the enzyme, the soluble fraction obtained from cell suspension homogenate was found to contain a small metastable organic molecule(s) which stimulated DGAT activity. Stimulation of microsomal DGAT by this factor was concentration dependent but not dependent on preincubation time.

Authors

• Byers, Susan D.
• University of Lethbridge. Faculty of Arts and Science

• Oilseed plants
• Fatty acids -- Synthesis
• Enzymes
• Canola oil
• Oilseeds
• Acyltransferases
• Phosphorylation
• Dissertations, Academic

Identifier

hdl:10133/101

OAI identifier oai:identifier

oai:opus.uleth.ca:10133/101