Biosynthesis of intestinal mucins. 2. Incorporation of [35S]sulphate by guinea-pig colon in vitro

Abstract

The mechanism of incorporation of S35 sulfate by guinea pig colon in vitro was studied and found to be an enzymic process requiring energy. Incorporated S35 was shown to be present as ester S35 sulfate in colonic mucin. The effects of added substrates on respiration, penetration by S35 sulfate, incorporation of S35 sulfate and total amino sugar content was measured. Sodium fluoroacetate, 2,4-dinitrophenol, phenol and salicylic acid inhibit respiration and incorporation of S35 sulfate. Glucose stimulates respiration, penetration by S35 sulfate and incorporation of S35 sulfate; sodium pyruvate stimulates respiration and incorporation of S35 sulfate; glucosamine stimulates incorporation of S35 sulfate. Whether the incorporation of S35 sulfate represents a net increase of mucin, or whether it is accompanied by an equivalent breakdown of preformed material was not determined.