Metal complexes with 2-(alpha-hydroxy-benzyl)thiamin pyrophosphate (HBTPP). Models for metal binding of thiamin enzymes
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Dodi, K.
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Πανεπιστήμιο Ιωαννίνων. Σχολή Θετικών Επιστημών. Τμήμα Χημείας
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Dodi, K.
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The reactions of MCl2 (M=Zn2+, Cd2+, Hg2+) With 2-(alpha-hydrOXy-benzyl)thiamin pyrophosphate (HBTPP) at various pH values (different protonation states) were studied in methanolic solutions. Solid complexes of formulae {K[Zn(HBTPP)Cl--(2)] . H2O}(m), {K-2[Cd(HBTPP)Cl-2-(2)] . 3H(2)O}(n), K-2[Hg(HBTPP)(2)-Cl-2] . 3H(2)O and Zn(HBTPP)(2)Cl-0(2) were isolated and characterized by elemental analysis and various NMR techniques, namely C-13 NMR, P-31 NMR, Cd-113 NMR, Hg-199 NMR and H-1 NMR ROESY spectra in D2O. The data provide evidence that Zn(II) in {K[Zn(HBTPP)Cl--(2)] . H2O}(n), and Cd(II) in {K-2[Cd(HBTPP)Cl-2-(2)] . 3H(2)O}(n), are coordinated both to the pyrimidine N(1') and to the pyrophosphate group. In contrast, Hg(II) in K-2[Hg(HBTPP)(2)Cl--(2)] . 3H(2)O and Zn(II) in Zn(HBTPP)(2)Cl-0(2) are bound only to the N(1') atom or to the pyrophosphate group, respectively. (C) 1999 Elsevier Science Inc. All rights reserved.
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