ena-STUDY-TU Darmstadt-03-01-2018-14:30:06:176-605
Influences of cysteine residues and hydrogen bond networks on enzyme activity of the persulfide dioxygenase from Acidithiobacillus caldus
Persulfide dioxygenases (PDO) are abundant in Bacteria but are also crucial for H2S detoxification in mitochondria. The pdo-gene of the acidophilic bacterium Acidithiobacillus caldus was expressed in Escherichia coli. The protein (AcPDO) had 0.77±0.1 Fe/subunit and an average specific sulfite formation activity of 111.5 U/mg protein (Vmax) at 40 °C and pH 7.5 with sulfur and GSH following a Michaelis-Menten kinetic. Gel permeation chromatography and non-denaturing gels showed mostly tetramers. The temperature optimum was 40-45 °C, the melting point 63±1.3 °C in thermal unfolding experiments, whereas some activity was measurable up to 95 °C.
Persulfide dioxygenases (PDO) are abundant in Bacteria but are also crucial for H2S detoxification in mitochondria. The pdo-gene of the acidophilic bacterium Acidithiobacillus caldus was expressed in Escherichia coli. The protein (AcPDO) had 0.77±0.1 Fe/subunit and an average specific sulfite formation activity of 111.5 U/mg protein (Vmax) at 40 °C and pH 7.5 with sulfur and GSH following a Michaelis-Menten kinetic. Gel permeation chromatography and non-denaturing gels showed mostly tetramers. The temperature optimum was 40-45 °C, the melting point 63±1.3 °C in thermal unfolding experiments, whereas some activity was measurable up to 95 °C.