Expression in Pichia pastoris and Functional Identification of Soybean GmCAT4 Gene

Bioinformatics analysis were conducted on the structure of soybean GmCAT4 protein,which encoded 492 amino acids. The molecular weight of the enzyme was 56. 7 kD,and the pI was 6. 80,the secondary and tertiary structures of the protein were predicted. After digested by both enzymes from pMD19-T-GmCAT4,the target gene was inserted into expression vector pPIC9K,and the yease strain Pichia pastoris was transformed by electrophoration with pPIC9K-GmCAT4. It was confirmed that soybean GmCAT4 gene was integrated into the yeast genome by PCR. After 96 h induction by methanol,the proteins in supernatant and cell lysates were measured by SDS-PAGE,and the activity of the crude liquid enzyme from the supernatant reached 124. 3 kU·L- 1. The transgene yeast strengthened its ability of salt and hydrogen peroxide tolerance.