The beta chain is a component of adult hemoglobins B. And C. Heterotetramer of either two alpha-B chains or two alpha-C chains and two beta chains. Hemoglobin C tetramers polymerize by the formation of disulfide bonds. The deoxy tetramers of hemoglobin B and C associate to form molecules believed to be trimers (B+2C) of very low oxygen affinity. Belongs to the globin family.