# Purification and characterization of the enzyme octaheme tetrathionate reductase

We are interested in the enzymes that some bacteria use to catalyze ammonia-nitrite interconversion, an ecologically important process. Nitrite reduction to ammonia is normally carried out by enzymes called cytochrome c nitrite reductases" (ccNiRs); however, another enzyme with unknown function called octaheme tetrathionate reductase (OTR) is also capable of catalyzing this reduction. For some of the long-term projects that our research group is involved in we anticipate that OTR will be easier to work with than ccNiR, and generate data that will be easier to interpret.