Vespalec R, Bartak P, Simanek V, Vlckova M.Electrophoretic
investigation of interactions of sanguinarine and chelerythrine
with molecules containing mercapto group.
J Chromatogr B Analyt Technol Biomed Life Sci. 2003 Nov
25;797(1-2):357-66.
Institute of Analytical Chemistry, Academy of Sciences of
Czech Republic, Veverí 97, CZ-611 42 Brno, Czech Republic.
vespalec@iach.cz
Using mercaptoethanol and (L)-cysteine as representatives of
mercapto compounds and capillary zone electrophoresis as
experimental technique, it was evidenced that sanguinarine and
chelerythrine do not react with the mercapto group of organic
compounds at pH 7.4. Their interaction is fast and reversible
complexation based on non-bonding intermolecular interaction in
which enter uncharged forms of sanguinarine or chelerythrine. A
negatively charged group, either bound to the mercapto ligand or
supplied from solution, participates in the complexation. Simple
1:1 interaction scheme reported in literature holds therefore
only for mercapto compounds bearing anionic group.
Stoichiometric binding constants corrected for the abundance of
the uncharged alkaloid form at pH 7.4 are of the order of
magnitude of 10(4) l/mol and depend on both cations and anions
of the background electrolyte. Interaction of sanguinarine and
chelerythrine with human or bovine serum albumins does not
qualitatively differ from their interaction with simple mercapto
compounds. Stoichiometric binding constants for the binding of
sanguinarine with human and bovine serum albumins in sodium
phosphate buffer pH 7.4, corrected for the abundance of the
interacting uncharged form, are 332,000+/-38,400 and
141,000+/-14,400 l/mol, respectively. The former agrees well
with the value K=385,000 (or log K=5.59) from static photometric
experiments. Constants for the complexation of uncharged
chelerythrine with human and bovine serum albumins are
2,970,000+/-360,000 and 1,380,000+/-22,600 l/mol, respectively.
PMID: 14630161 |
