Persulfide Dioxygenase From Acidithiobacillus caldus: Variable Roles of Cysteine Residues and Hydrogen Bond Networks of the Active Site.

ABSTRACT: Persulfide dioxygenases (PDOs) are abundant in Bacteria and also crucial for H₂S detoxification in mitochondria. One of the two pdo-genes 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 (V_max) at 40°C and pH 7.5 with sulfur and GSH following Michaelis-Menten kinetics. K_M for GSH and K_cat were 0.5 mM and 181 s^-1, respectively. Glutathione persulfide (GSSH) as substrate gave a sigmoidal curve with a V_max of 122.3 U/mg protein, a K_cat of 198 s^-1 and a Hill coefficient of 2.3 ± 0.22 sugge

SUBMITTER: Ruhl P 

PROVIDER: S-EPMC6060420 | biostudies-literature | 2018

REPOSITORIES: biostudies-literature