(3R)-1,4-thiomorpholine-3-carboxylate + NAD(+) => 3,4-dehydrothiomorpholine-3-carboxylate + NADH + 2 H(+)
(3r)-1,4-thiomorpholine-3-carboxylate + nad(+) => 3,4-dehydrothiomorpholine-3-carboxylate + nadh + 2 h(+)