CHEMICAL AND PHYSICAL-PROPERTIES OF HUMAN BRONCHIAL MUCUS GLYCOPROTEINS

Human bronchial mucus glycoproteins of different chemical types were isolated by Ecteola and gel exclusion chromatography. Chemical analysis indicated polydispersity with regard to content of sulfate and sialic acid. No blood group A, B or H activity was found in these glycoproteins. Compositions are reported for amino acid and sugar residues for several fractions obtained from both cystic fibrotic and chronic bronchitic mucus. It is noteworthy that glycoproteins extracted from a single subject contain molecules with different acid groups as well as significant differences in carbohydrate chain length. Molecular weights were found to be generally in the vicinity of 400.000. Length by electron microscopy was generally in the range 130-150 nm and corrected width about 3-5 nm. Molecular length distributions were generally broader than would be expected for homogeneous material indicating physical polydispersity. The general view obtained of these glycoproteins is that of an extended rod-like polypeptide stiffened by the presence of frequent glycosidic side chains. It is estimated that about one amino acid residue in three has a glycosidic side chain attached through a serine or threonine linkage. There is no obvious correlation between content of charged acidic groups and physical properties. A comparison of sedimentation coefficients calculated from the EM radius of gyration and the molecular weight was comparable to the measured sedimentation coefficient. © 1979 Masson, Paris.