a D-guloside + NAD(+) <=> a 3-dehydro-D-guloside + NADH + H(+)
a d-guloside + nad(+) <=> a 3-dehydro-d-guloside + nadh + h(+)
a D-guloside + NAD(+) <=> a 3-dehydro-D-guloside + NADH + H(+)
a d-guloside + nad(+) <=> a 3-dehydro-d-guloside + nadh + h(+)