The globulins are a family of globular proteins that have higher molecular weights than albumins and are insoluble in pure water but soluble in dilute salt solutions. Some globulins are produced in the liver, while others are made by the immune system. Globulins, albumin, and fibrinogen are the major blood proteins. The normal concentration of globulins in human blood is about 2.6-4.6 g/dL.