Pseudomonas siderophores: A mechanism explaining disease-suppressive soils

The membrane-bound hydrogenase ffomPseudomonas pseudoflava GA3 was purified up to a specific activity of 172 μmol H₂ oxidized/min and mg protein and a yield of 31%. The enzyme has a molecular weight of 98,000, consists of two different subunits (65,000 and 30,000), and contains 6 atoms iron and 6 molecules of acid-labile sulfide per molecule of enzyme. The isoelectric point was determined to be 6.5. The enzyme was stable under nitrogen, oxygen, and air atmosphere and unstable under hydrogen. The purified hydrogenase was able to reduce only a few of artificial electron acceptors, i.e., pyocyanine, methylene blue, phenazinemethosulfate, benzylviologen, and dichlorophenolindophenol.