ABSTRACT
Objective To clone the aldehyde dehydrogenase (adhA) gene from Methylovorus glucosotrophus and study its expression,purification and enzymatic characteristics.Methods The adhA gene was amplified and cloned to the expression vector pTIG.The AdhA was successfully expressed with induction in Escherichia coli BL21(DE3).The enzymatic characteristics were investigated by AHMT,and AdhA was purified by Ni+ exchange chromatography.Results AdhA accounted for more than 50% of the total cell proteins,and the purity was about 95%.With methanol as the substrate,the optimal pH of AdhA was 7.0,while the optimal temperature was 30℃.The enzymatic activity of purified AdhA remained about 60% when stored at room temperature for 6 days.Conclusion AdhA from MP688 is expressed in vitro,and methanol is the optimal substrate among all the substrates investigated.
ABSTRACT
Objective To prepare and characterize specific monoclonal antibodies( McAbs) against the heavy chain of botulinum neurotoxin serotype A ( BoNT/AHc ) .Methods BALB/c mice were immunized with purified BoNT/AHc protein.After the fusion of mouse splenic cells with SP2/0 cells, hybridoma cell lines secreted McAbs against BoNT/AHc. The McAbs obtained were characterized by indirect ELISA, Western blotting and rapid isotypingassay before being used in ELISA to detect interaction sites in McAbs and BoNT/AHc preliminarily.Results Antigen protein BoNT/AHc of high purification was obtained.Four hybridoma cell lines secreting McAbs against BoNT/AHc were screened,named 1A4,3H3, 3H7 and 5H8,respectively.Their titers of McAbs were all above 3.0 ×103 .They were specifically combined with BoNT/AHc protein by Western blotting.The isotype of 1A4 and 3H7 was IgG1(Κ),that of 3H3 was IgM(Κ),and that of 5H8 was IgG2b(Κ).Additive ELISA showed that epitopes recognized by the four McAbs were close.ELISA analysis confirmed the interaction epitopes in McAbs and BoNT/AHc.Conclusion Monoclonal antibodies against BoNT/AHc are prepared and characterized,providing effective tools for studying the neutralizing antibody and antibody epitopes of BoNT/AHc.