Rennin (Chymosin) is a proteolytic enzyme related to pepsin, produced in the stomachs of certain animals, that effectively coagulates liquid milk into a semi-solid form, prolonging its retention in the stomach. It specifically targets K-casein, cleaving the peptide bond between the amino acid residues phenylalanine and methionine (105 and 106), and plays a crucial role in cheese production [1].