phosphoethanolamine + L-serine + H(+) => L-serine-phosphoethanolamine + H2O
phosphoethanolamine + l-serine + h(+) => l-serine-phosphoethanolamine + h2o
phosphoethanolamine + L-serine + H(+) => L-serine-phosphoethanolamine + H2O
phosphoethanolamine + l-serine + h(+) => l-serine-phosphoethanolamine + h2o