(R)-glycerate + AH2 + H(+) => D-glyceraldehyde + A + H2O
(r)-glycerate + ah2 + h(+) => d-glyceraldehyde + a + h2o
(R)-glycerate + AH2 + H(+) => D-glyceraldehyde + A + H2O
(r)-glycerate + ah2 + h(+) => d-glyceraldehyde + a + h2o