Casein is not coagulated by heat. It is precipitated by acids and by rennin, a proteolytic enzyme obtained from the stomachs of calves. The enzyme trypsin can hydrolyze off a phosphate-containing peptone.
In addition to being consumed in milk, casein is used in adhesives, binders, protective coatings, and other products such as knitting needles. The purified protein is water insoluble. While it is also insoluble in neutral salt solutions, it is readily dispersable in dilute alkalis and in salt solutions such as sodium oxalate and sodium acetate.