Highly unsaturated fatty acids(HUFAs)are important constituents of cell membrane, and the unsaturated degree of carbon chain is an important factor in resisting to low temperature, maintaining and regulating the fluidity of cell membrane. In order to discover the key enzymes of synthetizing HUAs and their functions, using koi carp(Cyprinus carpiokoi)as studying materials, a 854 bp c DNA of delta 6 fatty acid desaturase(Fad6)was amplified by RT-PCR, their sequences were analyzed and the structures of protein...