N-terminal L-glutamyl-[protein] + L-leucyl-tRNA(Leu) <=> N-terminal L-leucyl-L-glutamyl-[protein] + tRNA(Leu) + H(+)
n-terminal l-glutamyl-[protein] + l-leucyl-trna(leu) <=> n-terminal l-leucyl-l-glutamyl-[protein] + trna(leu) + h(+)