Studies of Human Insulin from Nondiabetic and Diabetic Pancreas Free

Insulin has been isolated from single human pancreases from diabetic and nondiabetic sources. Purification was accomplished primarily by gel filtration. The average yield of insulin from the nondiabetic pancreas was 8.6 mg. per 100 gm. of tissue, and from the diabetic pancreas 2.9 mg. per 100 gm. The amino acid composition of nondiabetic insulin was in agreement with the known structure of human insulin. The insulin isolated from the diabetic pancreas had the same amino acid composition as normal human insulin in all cases but one. Based upon the amino acid analysis, it is possible that a different amino acid sequence occurs in the insulin from this diabetic source.