what is insulin made from
Early preparations of insulin were purified quite crudely from pancreas tissue extracted from animals-either pigs or cattle. Today, insulin is mostly made biosynthetically by recombinant DNA technology or 'genetic engineering'. Until the 1980s, all insulin was extracted from the pancreases of cattle and pigs. The sequence of amino acids (the building blocks that make up the protein) is slightly different in insulins from the different species. Compared to human insulin, porcine (pork) insulin has one different amino acid and bovine (beef) insulin three different amino acids.