Indolepyruvate ferredoxin oxidoreductase: An oxygen-sensitive iron-sulfur enzyme from the hyperthermophilic archaeon Thermococcus profundus

Thermococcus profundus is a strictly anaerobic sulfur-dependent archaeon that grows optimally at 80 degrees C by peptide fermentation. Indolepyruvate ferredoxin oxidoreductase (IOR), an enzyme involved in the peptide fermentation pathway, was purified to homogeneity from the archaeon under strictly anaerobic conditions. The maximal activity was obtained above the boiling temperature of water (105 degrees C), with a half-life of 62 min at 100 degrees C and 20 min at 105 degrees C. IOR was oxygen-sensitive with a half-life of 7 h at 25 degrees C under aerobic conditions. The specific activity of T. profundus IOR was found to be dependent on the number of [4Fe-4S] clusters in the enzyme. (C) 2012, The Society for Biotechnology, Japan. All rights reserved.