Size heterogeneity of human cervical mucus glycoproteins. Studies performed with rate-zonal centrifugation and laser light-scattering

Mucus glycoproteins (mucins) from cervical pregnancy mucus were fractionated by using rate-zonal centrifugation in a gradient of guanidinium chloride. The distribution of the macromolecules, as assessed by using sialic acid determination, suggested the presence of three populations of different size. Individual fractions were subjected to laser light-scattering performed as total-intensity measurements as well as photon correlation spectroscopy. The results showed that points of inflexion were present in the distribution of both Mr and DT (translational diffusion coefficient) and that the three populations have Mr values of approx. 24 X 10(6), 16 X 10(6) and 6 X 10(6) respectively. The weight-average Mr for the whole distribution, as calculated from the values obtained for the individual fractions, was 13.6 X 10(6), which is in good agreement with that found for the unfractionated material (11.1 X 10(6]. Plots of log RG (radius of gyration) and log (1/DT) versus log Mr are in keeping with the macromolecules being linear flexible chains.