Nickel-containing factor F430: chromophore of the methylreductase of Methanobacterium.

Abstract
The yellow chromophore of the methyl-coenzyme M methylreductase of M. thermoautotrophicum was found to be the Ni-containing factor F430. Treatment of 63Ni-labeled methylreductase with 80% aqueous methanol released the radiolabel and the yellow chromophore; both properties were associated with a single compound that was identical to F430, the stoichiometry being I mol Ni/mol F430 and 2 mol F430/mol of methylreductase.