Abstract：Abstract We firstly cloned a glyA gene that encoded serine hydroxymethyltransferase (SHMT) by PCR with the genomic DNA of Aeromonas hydrophila as template. The resulting glyA gene was ligated into vector pGEX-6p-1 to generate recombinant plasmid, pGEX-glyA. Then we transformed the recombinant plasmid into Escherichia coli DH5α. Sequence analysis revealed that the full length of glyA gene (GenBank accession: FJ797607) was 1 254 bp, and encoded a protein with a molecular weight of about 45 kD, composed of 417 amino acids. Further, we expressed the recombinant SHMT in E.coli by IPTG induction and purified the target protein using the GST-tag affinity chromatography. Enzymatic assay revealed that the recombinant SHMT displayed maximum activity at pH 8.0 and 20℃. The activity of SHMT was activated by Cu2+ and Mn2+, and inhibited by Zn2+ and SDS. The characterization of SHMT suggestes that SHMT is a cold-active serine hydroxymethyltransferase and has a potential significance for study of cold-active mechanism and industry applications.
