Insulin (Human) (C₂₅₇H₃₈₃N₆₅O₇₇S₆) — Properties, Uses & Safety

Overview

Insulin is a peptide hormone with the molecular formula C257H383N65O77S6 and a molar mass of approximately 5808 g/mol, making it one of the largest and most complex compounds commonly discussed in chemistry education. Produced by the beta cells of the pancreatic islets of Langerhans, insulin is the master regulator of blood glucose levels. When blood sugar rises after a meal, insulin signals cells throughout the body to absorb glucose from the bloodstream, lowering blood sugar back to normal levels. Insulin consists of two polypeptide chains — the A chain (21 amino acids) and the B chain (30 amino acids) — connected by two disulfide bonds between cysteine residues, with an additional intrachain disulfide bond within the A chain. At standard conditions, purified insulin is a white crystalline powder. It carries no significant GHS hazard codes in its pharmaceutical form. The discovery of insulin in 1921 by Frederick Banting and Charles Best at the University of Toronto is one of the most important breakthroughs in medical history, transforming type 1 diabetes from a fatal diagnosis into a manageable condition. Today, human insulin is produced using recombinant DNA technology — the human insulin gene is inserted into E. coli bacteria or yeast, which then produce insulin identical to the human form. This was one of the first commercial applications of genetic engineering. For chemistry students, insulin connects to numerous advanced topics: protein structure (primary, secondary, tertiary, and quaternary levels), disulfide bonds and their role in protein folding, peptide bond formation through condensation reactions, and the relationship between three-dimensional structure and biological function. Insulin also introduces biotechnology concepts including recombinant DNA, gene expression, and protein purification. The history of insulin — from animal-derived extracts to genetically engineered human insulin to modern fast-acting analogs — illustrates how chemistry and biology work together to improve human health.

IUPAC Name

insulin, human

CAS Number

11061-68-0

PubChem CID

118984335

Molecular Formula

C₂₅₇H₃₈₃N₆₅O₇₇S₆

Molar Mass

5807.63 g/mol

State at STP

solid

Appearance

White crystalline powder