Enzymatic Digestion of Mucoproteins. ∗

Abstract

Summary

1. Both rabbit and human seromucoproteins isolated by Winzler's method exhibited the same patterns of digestibility to enzymes. 2. They were digested completely by the common proteolytic enzymes, but only partially by collagenase, and human mucoproteins were only partially digested by activated human plasmin. 3. They were not digested by the amylases nor lysozyme. 4. However, mucoproteins were digested by enzymes combining proteolytic and diastase splitting activities. 5. The mucoproteins as conjugated proteins seem to be less susceptible to attack through the carbohydrate than through the protein moiety. 6. Some portions of human mucoproteins, unlike the mucoproteins from the rabbits, were found to be less stable on standing in phosphate buffer pH 7.1 at room temperature, to incubation, and to prolonged contact with 0.75M perchloric acid. 7. Quantitatively the mucoproteins that increase in serum after injury should be reduced in amount by the proteolytic enzymes that increase also during exudation. However human seromucoproteins are not too susceptible to the action of plasmin present in serum and the trypsin-like enzymes found abundantly in leukocytes are not found in the human and in the rabbit are only discharged locally.