RESUMO
From a series of 17 different submandibular glands the mucins were isolated. Between 0.78 and 1.85 mg mucin was obtained per g of tissue. In correspondence with the literature the differences in sugar composition between substances with A-, B-, Le a- and Le b- blood group specificity were correlated with the serological specificities observed. Thus galactosamine, galactose and fucose were relatively the highest in the A-, B- and Le b- active substances, respectively. The influenza virus haemagglutination inhibition capacity for a number of human submandibular mucins was determined in comparison with the ovine, bovine and mouse sublingual mucins. The human submandibular mucins with the highest sialic acid content were the most active in inhibiting the haemagglutination. Independent of the serological specificity the same amino acid composition was found. However, a comparison with the results obtained by other workers revealed that the composition may partly depend on the method of isolation. On this basis it has been tentatively concluded that the salivary mucins contain at least two protein cores, one of which is very rich in serine and threonine, the other being preferentially removed by treatment with proteolytic enzymes or - s - s - bonds splitting agents.(AU)