Copper(II) increases bile acid binding to asparagine.
Interactions of two bile acids (cholic and glycocholic acids) with asparagine have been studied by potentiometry in aqueous solutions under conditions similar to those observed in biological fluids (37 degrees C and I = 0.15 M NaCl), and in the absence and presence of copper(II). To characterize the equilibria for the systems copper(II)/bile acid/asparagine, specifically to assess cooperative binding between bile acids and asparagine, the acidity constant of asparagine and formation constants for copper(II)/bile acid and copper(II)/asparagine were also obtained under the same conditions. The results obtained suggest cooperativity in the binding of bile acid to asparagine in the presence of copper(II).
de Castro
B
B
CEQUP/Departamento de Química, Faculdade de Ciências, Universidade do Porto, Portugal.
Lima
J L
JL
Mayer
I H
IH
Reis
S
S
D001216:Asparagine / Q000737:chemistry*; D001647:Bile Acids and Salts / Q000737:chemistry*; D003300:Copper / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration
D001647:Bile Acids and Salts; D001216:Asparagine; D003300:Copper