Involved in glucose metabolism. Heterodimer of a B chain or a B chain' and an A chain probably linked by three disulfide bonds. Expressed in the central region of the cerebral ganglia mostly within the F and C clusters. Insulin A chain. Insulin B chain. Insulin B chain'. Insulin (AI) with the disulfide bonds. The measured ranges are 32-76, 105-139. Insulin (AI') with the disulfide bonds. The measured ranges are 32-72, 105-139. Belongs to the insulin family.