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