Insulin is a type of hormone. Insulin is the hormone released from the beta (β) cells of the pancreas that controls diabetes by accelerating the uptake of blood glucose. Insulin is a type of small protein. Pro-insulin consists of four parts. Anterior part and A, B and C parts. Insulin is made by removing the C portion of pro-insulin and joining the A and B portions by a disulfide bond. Human insulin contains 17 types of 51 amino acids. Its chemical symbol is C254H377N65O75S6 and molecular mass is 5734. The DNA molecule at the top of the short arm of human chromosome 11 contains the insulin producing gene. It consists of 153 nitrogenous bases. E. coli bacteria contain 1×105 (10 lakh) insulin molecules.