ACHAIN

A-chain: translation

Shorter of the two polypeptide chains of insulin (21 residues compared to 30 in the B chain). Many other heterodimeric proteins have their smaller chain designated the A chain, so the term cannot be used without qualification. Other A chains: abrin, activin, C1q (see complement), diphtheria toxin, inhibin, laminin, mistletoe lectin, PDGF, relaxin, ricin, TPA.