SYNTHESIS OF THE LEU-ENKEPHALIN GENE

The synthesis of Leu-enkephalin gene by an alternative approach was described in thispaper. The sequence of the synthetic gene, 26 base-pairs in length, was derived from the ami-no acid sequence of the hormone peptide Leu-enkephalin. It bears single-stranded cohesive ter-mini for the restriction endonucleases EcoR I and BamH I so that it may be inserted into apBR 322 plasmid. The 4 deoxyoligonucleotide fragments, varying in length from octanucleotideto octadecanucleotide, were synthesized by an improved phosphotriester method developed inour laboratory. All chemically synthetic fragments were pure and had the correct sequences.The assembly of the Leu-enkephalin gene was carried out in a one-step ligation reaction cata-lysed by T-DNA ligase with good yield, Finally, the purified products from polyacrylamidegel electrophoresis had the correct joining-points as predicted.