n. an enzyme produced in the stomach that coagulates milk. It is secreted by the gastric glands in an inactive form, prorennin, which is activated by hydrochloric acid. Rennin converts caseinogen (milk protein) into insoluble casein in the presence of calcium ions. This ensures that the milk remains in the stomach, exposed to protein-digesting enzymes, for as long as possible. The largest amounts of rennin are present in the stomachs of young mammals.... rennin
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