The invention relates to methods and compositions concerning desaturase enzymes that modulate the number and location of double bonds in long chain poly-unsaturated fatty acids (LC-PUFA's). In particular, the invention relates to methods and compositions for improving omega-3 fatty acid profiles in plant products and parts using exogenous desaturase enzymes and nucleic acids encoding for such enzymes. In particular embodiments, the exogenous desaturase enzymes utilized are Hemiselmis spp. delta 5 desaturases. Also provided are improved soybean oil compositions having EPA derived from plants carrying the genes of interest.
