Phase transition of human gastrointestinal mucin solutions

Abstract

In this study, we investigate the phase behavior of mucin aggregates from gastrointestinal mucus in the addition of multivalent salts. A reentrant phase transition is observed with trivalent and tetravalent salts. Mucin aggregates exhibit liquid-solid phase separation in divalent salts such as Ca2+, Cu2+ and Ba2+, whereas the solution remains homogeneous across all tested concentrations of MgCl2. The ability of multivalent salts in promoting protein participates follows the order: spermine>Fe3+>Al3+>Ba2+>Cu2+>Ca2+>Mg2+, which is different from the Hofmeister series. Whats more, precipitates formed in CaCl2solution can be redissolved through ion exchange by adding NaCl or MgCl2.