selenol Se-methyltransferase activity

Definition

Target type: molecularfunction

Catalysis of the reaction: R + Se-Adenosylselenomethionine => CH3-R + Se-Adenosyl-L-selenohomocysteine. [PMID:1711890]

Selenol Se-methyltransferase activity catalyzes the transfer of a methyl group from a donor molecule, such as S-adenosyl methionine (SAM), to a selenol (-SeH) group on a substrate. This reaction involves the formation of a transient covalent intermediate between the enzyme and the donor molecule, followed by the transfer of the methyl group to the selenol. The resulting product is a selenoether (-SeCH3), which often has altered properties compared to the original selenol. Selenol Se-methyltransferases play a crucial role in a variety of biological processes, including the biosynthesis of selenoproteins, the detoxification of reactive oxygen species, and the regulation of enzyme activity. For example, in the biosynthesis of selenoproteins, selenol Se-methyltransferases are involved in the post-translational modification of selenocysteine residues, converting them to selenomethionine residues. These selenoproteins are essential for a wide range of cellular functions, including antioxidant defense, thyroid hormone metabolism, and DNA synthesis. In detoxification, selenol Se-methyltransferases can methylate toxic selenols, rendering them less reactive and facilitating their excretion. Furthermore, selenol Se-methyltransferases can regulate enzyme activity by altering the properties of selenol residues within active sites, influencing their catalytic activity and substrate specificity. The specific functions of selenol Se-methyltransferases vary depending on the enzyme and its substrate. However, all selenol Se-methyltransferases share the common function of catalyzing the transfer of a methyl group to a selenol group, thereby influencing the properties and functions of the target molecule.'
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Proteins (1)

Compounds (2)