Hyperproduction of a bifunctional hybrid protein, metapyrocatechase-protein A, by gene fusion

A hybrid protein between metapyrocatechase and Staphylococcal protein A was produced by recombinant DNA techniques. A plasmid carrying the fusion gene that encodes the hybrid protein was constructed and expressed in E. coli. Over 70% of soluble proteins of the cell extracts was estimated to be the hybrid protein. This fusion protein is about 65000. Both the IgG-binding activity of protein A and the metapyrocatechase activity were found in the hybrid protein. The optimum pH of metapyrocatechase in the fusion protein was at around 6.5 and K m was 1.3 × 10 −5 M. A simple immuno-enzymometric assay was developed for anti-BSA antibody using the fusion protein.