what is rennet in cheese

Rennet is a key ingredient in cheesemaking, comprised of enzymes that coagulate milk and separate solid curds from liquid whey. It is a complex set of enzymes, with its key component being chymosin, a protease enzyme that curdles the casein in milk. Traditionally, rennet was harvested from the stomach lining of young cows, sheep, and goats, but today it is also produced from vegetable and microbial sources, as well as genetically modified animal enzymes. Most cheeses contain rennet, and it is essential for the process of converting milk to cheese