L-homocysteine + L-serine => L,L-cystathionine + H2O
l-homocysteine + l-serine => l,l-cystathionine + h2o
L-homocysteine + L-serine => L,L-cystathionine + H2O
l-homocysteine + l-serine => l,l-cystathionine + h2o