OBSERVATIONS ON THE SALIVARY MUCOLYTIC ENZYMES

¹ Institute of Dental Research, United Dental Hospital, Sydney, and Department of Biochemistry, University of Sydney, Sydney, Australia

The mucinase activity of saliva has been measured by three methods, viz., decrease in ACRA titer, decrease in precipitable carbohydrate, and decrease in viscosity.

The variation in enzyme titer has been investigated; it is concluded that the titer varies during the day and from day to day in one person, and that there is some variation from person to person.

Salivary mucinase has been partly purified by precipitation with acetone, alcohol, and ammonium sulfate, and adsorption onto kaolin or alumina C followed by elution with M/15 (NH₄)₂HPO₄.

The properties of salivary mucinase have been studied. The enzyme is inactivated below pH 4.5 and above pH 11.0; also heating at 55° C. for two minutes destroys the enzyme. Studies of possible activators and inhibitors suggest that the enzyme does not require the presence of sulfhydryl groups, but is activated by magnesium.

Several microorganisms with mucolytic activity have been isolated from saliva, and the production of an exocellular mucolytic enzyme has been demonstrated.

The results suggest that there is a relationship between the hydrolysis of starch and gelatin on the one hand, and the ability to depolymerize salivary mucoid on the other hand.

The mucolytic activity of single strains of bacteria has been found to vary unaccountably, and attempts to increase the mucolytic activity were unsuccessful.