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Updated: Jul 29, 2026

Mixed Primary Cultures of Murine Small Intestine Intended for the Study of Gut Hormone Secretion and Live Cell Imaging of Enteroendocrine Cells
Published on: April 20, 2017
Stimulation of proteolytic digestion by intestinal goblet cell mucus
Abstract:
Intestinal goblet cell mucus (GCM) was added to incubations of casein and trypsin (or chymotrypsin) to discover whether mucus could inhibit proteolysis. Contrary to expectation, GCM stimulated casein hydrolysis, reaching a maximum effect at a GCM to casein ratio (w/w) of 0.083. GCM did not contain proteolytic enzymes or proenzymes as contaminants, nor did GCM serve as a substrate for trypsin. Stimulation was not reduced by removing 85% of the sialic acid from GCM. Harsh physical treatment (boiling and freezing) of casein decreased (50%) the GCM effect, as did partial predigestion of casein by trypsin, and elevation of trypsin concentration beyond 3 mug per ml. Thus the undegraded structure of casein appeared to be important for the stimulation of proteolysis by GCM. GCM also enhanced the hydrolysis by trypsin of intestinal brush border membrane protein, but had no effect on the hydrolysis of hemoglobin, albumin, or benzoyl arginine ethyl ester. These results suggest that GCM reacts with specific substrates, in a fashion which promotes their digestion by trypsin or chymotrypsin.
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