label: Co(II)-factor III + AH2 + S-adenosyl-L-methionine <=> Co-precorrin-4 + A + S-adenosyl-L-homocysteine
label_lc: co(ii)-factor iii + ah2 + s-adenosyl-l-methionine <=> co-precorrin-4 + a + s-adenosyl-l-homocysteine