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