How many types of insulin by source?

Many types of insulin, classification, can be the source of the production process, the role of time, the purity of classified, in accordance with the source of which can be divided into the following categories:
Animal insulin: is extracted from the pancreas of pigs or cattle, are not identical in their amino acid structure of human insulin, the impurity content, the lowest efficiency antigen and strong. Animal insulin has been rarely used in developed countries and regions, because of its cheap, still in use in China's rural grass-roots hospitals. Should be noted that animal insulin into human insulin dose should be reduced by 15% to 20%, or it may increase the risk of hypoglycemia.
(2) human insulin: is the use of recombinant DNA technology to produce self-generated structure is exactly the same insulin, it overcomes the shortcomings of animal insulin, and free of impurities, high titer, weak antigenicity. Human insulin is currently the most widely used insulin, its representative product the Novolin series the Humulin series and the domestic Gansulin series insulin.
Porcine insulin: from porcine pancreas extract from molecules in only one amino acid different from human insulin, which means that it is the closest to human insulin structure, so the high efficacy, low antigenicity, our own production of insulin mainly porcine insulin preparations, including the current production of the highest purity the Xuzhou neutral insulin or porcine insulin .