L-selenohomocysteine: one-step synthesis from L-selenomethionine and kinetic analysis as substrate for methionine synthases

A single-step convenient synthesis of -selenohomocysteine (SeHcy) from -selenomethionine (SeMet) using sodium in liquid ammonia is described. Methionine synthases convert SeHcy to SeMet at rates comparable to their rates of conversion of -homocysteine (Hcy) to -methionine (Met). This study suggests that SeHcy generated from SeMet metabolism can be efficiently recycled to SeMet in mammals.