An albuminous body, insoluble in water, but soluble in dilute solutions of salt. It is present in the red blood corpuscles united with hæmatin to form hæmoglobin. It is also found in the crystalline lens of the eye, and in blood serum, and is sometimes called crystallin. In the plural the word is applied to a group of proteid substances such as vitellin, myosin, fibrinogen, etc., all insoluble in water, but soluble in dilute salt solutions.
- Any of a class of proteins that are found extensively in blood plasma, milk, muscle, and plant seeds and that are insoluble in pure water and half saturated ammonium sulfate, soluble in dilute salt solution, and coagulable by heat.