(6R)-5,10-methenyltetrahydrofolate + H2O <=> (6S)-5-formyl-5,6,7,8-tetrahydrofolate + H(+)
(6r)-5,10-methenyltetrahydrofolate + h2o <=> (6s)-5-formyl-5,6,7,8-tetrahydrofolate + h(+)
(6R)-5,10-methenyltetrahydrofolate + H2O <=> (6S)-5-formyl-5,6,7,8-tetrahydrofolate + H(+)
(6r)-5,10-methenyltetrahydrofolate + h2o <=> (6s)-5-formyl-5,6,7,8-tetrahydrofolate + h(+)