α-Chymotrypsin (CT) closely denotes a group of digestive enzymes (trypsin, elastase) th at hydrolyzes polypeptide chains. The catalytic triad system works together to regulate the nucleophilicity of the serine residue in catalysis. CT shows a capability to catalyze nonconventional synthetic reactions in water-miscible organic media. Additionally, it is also used as a tool in comparative studies of water-miscible and water-immiscible solvents.