cobyrinic acid

co·byr·in·ic ac·id

(kō'bir-in'ik as'id),
Corrin with 8 methyl groups at positions 1, 2, 5, 7, 12 (2), 15, and 17; -CH2COOH groups at positions 2, 7, and 18; -CH2CH2COOH groups at positions 3, 8, 13, and 17; and divalent cobalt centered among the four nitrogens. The acid side chains are designated, in numeric order, a, b, c, d, e, f, and g. It is a part of the vitamin B12 structure.