Structure/function studies of arsenite oxidoreductase and xanthine oxidase

The recently solved X-ray crystal structure of the molybdenum-containing arsenite ox idoreductase from Alcaligenes fa ecalis, is discussed, keeping in view the known mechanistic and spectroscopic information regarding the protein in a structural context. In addi tion, recent mechan istic studies of );,janthine oxidase are covered , with the conclusion that the reaction meclianism is initiated by nuclcophilic attack of a Mo-OH group on substrate.