Structure and Substrate Specificity of -Methyl Thiourocanate Hydratase.

Nicotinamide adenine dinucleotide (NAD) is a common cofactor in enzyme-catalyzed reactions that involve hydride transfers. In contrast, urocanase and urocanase-like enzymes use NAD for covalent electrophilic catalysis. Deciphering avenues by which this unusual catalytic strategy has diversified by evolution may point to approaches for the design of novel enzymes.

Enzyme-Catalyzed Oxidative Degradation of Ergothioneine.

Ergothioneine is a sulfur-containing metabolite that is produced by bacteria and fungi, and is absorbed by plants and animals as a micronutrient. Ergothioneine reacts with harmful oxidants, including singlet oxygen and hydrogen peroxide, and may therefore protect cells against oxidative stress. Herein we describe two enzymes from actinobacteria that cooperate in the specific oxidative degradation of ergothioneine.