On the role of peripheral interactions in specificity of chymosin

Chymosin is distinguished by a high level of milk-clotting activity which is the consequence of the specific cleavage of the Phe(105)-Met(106) bond of kappa-casein. Based on modelling considerations it was proposed that milk-clotting activity of chymosin is associated with electrostatic interactions of a charged segment His-Pro-His-Pro-His (98-102) of casein and the outer loop of the enzyme containing Glu-244,Asp-246 and Asp-248.