Fig.4

3.4 Optimal temperature

The optimal reaction temperature of free D-amino acid dehydrogenase with peptide linker was investigated. As it can be seen from Fig.5, the optimal temperature was 40 ℃. Relative activity could keep above 80% at 40-80 ℃, the relative activity was 97.7% at 80 ℃. The results showed that the DAADH can maintain high catalytic activity under high temperature. In high temperature such as 70-80 ℃, peptide linker cause conformation adjustment of enzyme, which may obtain high activity.