cob(III)alamin + AH2 <=> cob(I)alamin + A + 2 H(+)
cob(iii)alamin + ah2 <=> cob(i)alamin + a + 2 h(+)
cob(III)alamin + AH2 <=> cob(I)alamin + A + 2 H(+)
cob(iii)alamin + ah2 <=> cob(i)alamin + a + 2 h(+)