The protein that is formed under the influence of acid or enzyme is called primary produced protein. The primary proteins produced are:
(i) Proteins: Proteins are formed by the reaction of dilute acids, enzymes and water. It is insoluble in water. Edestin to edestan, myosin to myosin, fibrinogen to fibrin, etc.
(ii) Metaprotein: Metaprotein is insoluble in water. But soluble in mild acid and alkali. For example, acid metaprotein, alkaline metaprotein etc.
(iii) Denatured protein: Denatured protein is produced by the effect of heat or alcohol on the protein. It is insoluble in water. For example, the white part of the coagulated egg.