This book provides, through X-ray crystallography, information about the structure and function relationships of urease and cytochrome c-553 from Bacillus pasteurii. Urease is a nickel enzyme involved in nitrogen turnover and in human and animal pathologies. The comparison between the native and the inhibited structures provides information about the active site and the inhibition mechanisms, and allows the proposal of a reaction mechanism which agrees with the available biochemical data. Cytochrome c-553 is a small electron transfer protein. The characterisation at atomic...