Chymosin milk-clotting action

Chymosin is secreted by the abomasum in the form of an intially inactive precursor, prochymosin, which is converted autocatalytically to chymosin (see below, p. 176). Many reviews on the properties of the zymogen and the enzyme have been published. One of the most recent, by Foltmann (J), also contains references to earlier reviews. The action of chymosin on K-casein is primarily responsible for the milk-clotting process. The numerous studies of this reaction have been reviewed recently by Mackinlay and Wake (32). Because of the number of diflFer-ent milk proteins and the complexity of their interactions, especially in the casein micelle, the full details of the coagulation process are not yet understood. 

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