Preliminary safety assessment of a membrane-bound delta 9 desaturase candidate protein for transgenic oilseed crops

► Membrane-bound delta 9 desaturase proteins is very difficult to express. ► Purification of delta 9 desaturase after over expression is very challenging. ► In vivo toxicological studies are not feasible with delta 9 desaturase. ► Alternate human health safety assessment is necessary for membrane proteins. ► Studies with partially enriched delta 9 desaturase were used to demonstrate safety. A gene encoding delta 9 desaturase (D9DS), an integral membrane protein, is being considered for incorporation into oilseed crops to reduce saturated fatty acids and thus improve human nutritional value. Typically, a safety assessment for transgenic crops involves purifying heterologously produced transgenic proteins in an active form for use in safety studies. Membrane-bound proteins have been very difficult to isolate in an active form due to their inherent physicochemical properties. Described here are methods used to derive enriched preparations of the active D9DS protein for use in early stage safety studies. Results of these studies, in combination with bioinformatic results and knowledge of the mode of action of the protein, along with a history of safe consumption of related proteins, provides a weight of evidence supporting the safety of the D9DS protein in food and feed.