The heterologous overexpression level of the bacterial dye decolorizing peroxidase Tfu DyP in Escherichia coli was increased sixty fold to approximately 20002mg of purified enzyme per liter culture broth by fusing the enzyme to the small ubiquitin-related modifier protein (SUMO). The highly overexpressed SUMO- Tfu DyP was, however, almost inactive. Analysis of the enzyme by UV–vis absorption spectroscopy and high-resolution mass spectrometry showed that a large fraction of the highly overexpressed enzyme contained the iron deficient heme precursor protoporphyrin IX (PPIX) instead of heme. Here we show that the activity of the enzyme was dependent on the expression level of the protein.
The heterologous overexpression level of the bacterial dye decolorizing peroxidase Tfu DyP in Escherichia coli was increased sixty fold to approximately 20002mg of purified enzyme per liter culture broth by fusing the enzyme to the small ubiquitin-related modifier protein (SUMO). The highly overexpressed SUMO- Tfu DyP was, however, almost inactive. Analysis of the enzyme by UV–vis absorption spectroscopy and high-resolution mass spectrometry showed that a large fraction of the highly overexpressed enzyme contained the iron deficient heme precursor protoporphyrin IX (PPIX) instead of heme. Here we show that the activity of the enzyme was dependent on the expression level of the protein.
