[Expression, Purification and Bioinformatics Analysis of β-hexosaminidase of Dermatophagoides farinae].

The DNA fragment encoding β-hexosaminidase was synthesized, and cloned into pET-28a vector. The constructed plasmid pMD18-T-β-hexosaminidase was transformed into E. coli Top 10 and followed by expression of the protein induced by IPTG. SDS-PAGE result showed that the relative molecular mass of the recombinant protein was about M, 55 000. The full length of β-hexosaminidase gene was 1 410 bp. Bioinformatics analysis revealed that β-hexosaminidase was composed with 469 amino acid residues with a calculated molecular weight of Mr 55,000, and its secondary structure was composed of strand (14.71%), helix (30.70%), and loop (54.58%). β-hexosaminidase was a hydrophilic protein without signal peptide, and located in the extracellular space.