Bioactive peptides from natural sources are currently favorable. Fruit seeds are sources of accumulated food, so there are potential sources for discovering bioactive peptides. In this research, two antioxidative peptides from longan seeds, Longan 1 (ISYVVPVYIAEITPKTFRGGF) and Longan 2 (TLAMHYF) were selected. However, direct extraction of the peptides from natural sources encounters some problems such as low yield of peptide. To overcome these problems, molecular genetic technique is chosen in this research by designing DNA fragment containing 4 copies of the peptide Longan 1 linked by the codons of Aspartic acid and DNA fragment containing 10 copies of the peptide Longan 2 linked by the codons of Lysine in oder to obtain adequetly long peptides for being manipulated by molecular genetic teqnique. Then, both DNA fragments were inserted into the expression vector, pPICZαA and further integrated onto P. pastoris GS115 chromosome for producing those peptides. For this research, two strains of P. pasotoris, TWLG1PP and WPLG2, were constrcted for producing peptide Longan 1 and Longan 2, respectively. For the strain TWLG1PP, nucleotide sequence was already verified. However, the strain WPLG2 was preliminary verified while nucleotide sequence verification is in progress. Then, both strains will be induced to express recombinant peptides. The rerombinant petide from TWLG1PP strain will further cut by Endoproteinase AspN while that from WGLG2 will further cut by trypsin Carboxyldase B. Next, antioxidative and antiproliferative activities will be tested.
