||Bacteria Escherichia coli
||Axley MJ, Böck A, Stadtman TC. Catalytic properties of an Escherichia coli formate dehydrogenase mutant in which sulfur replaces selenium. Proc Natl Acad Sci U S A. 1991 Oct 188(19):pp. 8452PubMed ID1924303
||Enzyme activity was determined as a function of formate and BV (benzyl viologen) concentrations.
||Kcat of original fdh with selenocysteine is 2800 1/sec. In mutant (s)fdh with cysteine replacing selenocysteine kcat=9 1/sec. The diminished catalytic activity is due to a rate of formate oxidation (k2) that is three orders of magnitude lower for [S]FDHH.