1.6 kb Δ4-desaturase gene(FAD4)was amplified by PCR using plasmid pGEM-TFAD4 as template. The fragment was subcloned into the HindⅢ/XbaⅠrestriction site of pYES2.0 vector. Recombinant plasmid pYFAD4 was transformed into Saccharomyces cerevisiae strain INVScl for expression.It was found to exhibit Δ4-fatty acid desaturase activity in the recombinant S.cerevisiae YFAD4 in the presence of exogenous fatty acid substrate docosapentaenoic acid(100μmol/L)under introduction of GAL1.Expression of the FAD4 under appropriate media and temperature conditions led to the production of DHA and it reached 41.13％ of the total yeast fatty acid by GC detection.It was suggested that the protein encoded by FAD4 could specifically catalyze DPA into DHA.
