Compound as reactive (1)

Se-methyl-L-selenocysteine → dimethyl diselenide

Compound as product (1)

S-adenosyl-L-methionine + L-selenocysteine → S-adenosyl-L-homocysteine + H⁺ + Se-methyl-L-selenocysteine

Reversible reaction (1)

S-methyl-L-methionine + L-selenocysteine ↔ H⁺ + L-methionine + Se-methyl-L-selenocysteine