Isolated proteins which are at least partially encoded by polynucleotide sequences encoding novel desaturases are provided together with a composition which includes these isolated proteins. A transgenic plant, a transgenic alga, or a transgenic seed transformed by the polynucleotides encoding proteins which are at least partially encoded by novel desaturases are also provided. The invention also includes a process for making a very long-chain polyunsaturated fatty acid in a transformed cell, a transgenic alga, or a transgenic plant expressing the isolated protein or proteins which are at least partially encoded by the polynucleotide sequences encoding novel Δ5, Δ6, or Δ12 desaturases.
