Light scattering studies of the effect of Ca2+ on the structure of porcine submaxillary mucin

✍ Scribed by B. K. Varma; A. Demers; A. M. Jamieson; J. Blackwell; Neil Jentoft

• Publisher: Wiley (John Wiley & Sons)
• Year: 1990
• Tongue: English
• Weight: 605 KB
• Volume: 29
• Category: Article
• ISSN: 0006-3525
• DOI: 10.1002/bip.360290214

✦ Synopsis

Abstract

The effects of calcium ions on the solution properties of porcine submaxillary mucin (PSM) have been investigated by static and dynamic light scattering. The weight average molecular weights of PSM fractions are unaffected by the addition of up to 0.5__M__ CaCl~2~: these data are within experimental error of those for solutions in 0.1__M__ NaCl. The distribution of relaxation frequencies derived from the dynamic data shows the existence of two distinct relaxation modes. The average relaxation times have been interpreted to yield the z‐average translational diffusion coefficient and the longest intramolecular relaxation time τ~1~. A plot of τ~1~ vs 〈1/R~h~〉 is linear, and consistent with plots of such data recorded for PSM in 0.1__M__ NaCl and 6__M__ GdnHCl solutions. However, the τ~1~ values and the associated results for 〈R〉 in 0.5__M__ CaCl~2~ are smaller than those determined in 0.1__M__ NaCl. This suggests that the conformation of PSM in CaCl~2~ solution is more contracted than those in the other two solvents. These results are consistent with the compact packaging of mucin in the secretary granules that have elevated Ca^2+^ levels.