Properties of a 2,3-Butanediol Dehydrogenase from Taiwanofungus camphorata.

2,3-Butanediol dehydrogenase (Bdh) plays important roles in reduction of acetoin to 2,3-butanediol, an important platform chemical with many industrial applications. Here, a TcBdh cDNA (1348 bp, GenBank accession JF896462) encoding a putative Bdh was cloned from Taiwanofungus camphorata. The deduced amino acid sequence is similar to the Bdhs from other species. A 3-D structural model of TcBdh has been constructed based on the known structure of Pseudomonas putida formaldehyde dehydrogenase ( PpFdh, PDB code 1KOL). To characterize the TcBdh protein, the coding region was subcloned into an expression vector pYEX-S1 and transformed into Saccharomyces cerevisiae. The recombinant His6-tagged TcBdh was expressed and purified by Ni2+-nitrilotriacetic acid Sepharose. The purified enzyme showed a single band of 49 kDa on 12% sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The Michaelis constant ( KM) value of the recombinant enzyme for acetoin was 8.5 mM. The enzyme's optical pH was 6. The thermal inactivation of the enzyme showed a half-life of 5.3 min at 45 °C. [ABSTRACT FROM AUTHOR]