The enzyme rennin is responsible for the digestion of what?

Rennin, also known as chymosin, is an enzyme primarily responsible for the digestion of casein, a major protein found in milk. It plays a crucial role in the curdling of milk, which is essential for cheese production and for infants' digestion of breast milk. By coagulating casein, rennin helps facilitate the breakdown of proteins in the digestive system.