Observations on the Salivary Mucoids

Abstract

The mucoid content of saliva was measured by a method depending on the precipitability in an acid-alcohol mixture (ACRA method). It was found that there is a wide variation in the mucoid content of saliva from the one person. Precipitation by citric acid was chosen as the most suitable method for obtaining salivary mucoid. Resting saliva was ejected directly into a tube containing the acid (final concn. approx. 0.02 [image]) and centrifuged. The floating clot of mucoid was dissolved in 0.5% Na2CO3 to give a viscous soln. which, after neutralizing with HCl, was readily depolymerized by salivary mucinase. Analysis showed 7% total N, 34% hexosamine and a trace of P and S. Uronic acid was absent. The prepn. differed from the mucoid in whole saliva in that it was more readily depolymerized by heat and was precipitated by 0.1[image] HCl. It is suggested that these differences may be due to the fact that whereas the product in vivo is believed to be a Ca mucinate the isolated product would be the Na salt. The dialyzed mucoid showed weak buffering capacity and this was increased on incubation with enzyme. From the results obtained the possible role of salivary mucoid in the formation of the dental plaque is discussed.