As a first step in the incorporation of selenomethionine into proteins, tRNA(Met) is converted into selenomethionyl-tRNA(Met) (SeMet-tRNA(Met)) by methionine-tRNA ligase (MARS) component of a multisynthetase complex comprised of a bifunctional glutamyl-prolyl-tRNA synthetase, the monospecific isoleucyl, leucyl, glutaminyl, methionyl, lysyl, arginyl, and aspartyl-tRNA synthetases as well as three auxiliary proteins, p18, p48 and p43. It is involved in the selenomethionylation of tRNA(Met) into selenomethionyl-tRNA(Met) (SeMet-tRNA(Met)). This reaction is inferred from the event in mung bean (Burnell 1981) and in wheat germ (Eustice et al. 1981).