ISBN: 978-83-60043-10-3 - eurobic9

Eurobic9, 2-6 September, 2008, Wrocław, Poland
P86. Equilibrium Studies of Phytic Acid Interactions with Spermine
R. Jastrzab a , A. Odani b , L. Lomozik a , R. Bregier-Jarzebowska a
a
Faculty of Chemistry, A.Mickiewicz University, Grunwaldzka 6, 60-780, Poznan, Poland
e-mail: renatad@amu.edu.pl
b
Graduate School of Natural Science and Technology, Kanazawa University, Kakuma-machi, 920-1192,
Kanazawa, Japan
The in vivo as well as in vitro studies have shown that phytic acid (IP6) is an important antioxidant and the
presence of IP6 in living cells has beneficial effects, such as protection against cancer, heart diseases and renal
calculosis [1, 2]. A large number of phosphate groups (Figure) provide strong multidonor interaction sites in the
ligand that take part in reactions with metals or organic cations, e.g. polyamines [3].
Polyamines are present in the physiological fluids as protonated species and in this form interact with negative
fragments of other bioligands including IP6. The mechanism of such an action at the molecular level has not
been recognised yet.
This presentation shows results of the potentiometric equilibrium study of the interactions of phytic acid with
spermine and other polyamines. To characterise the mode of interactions, the systems studied have been
investigated by 31 P NMR. The noncovalent interactions between partly protonated spermine and partly
deprotonated phosphate groups of phytic acid lead to the formation of molecular complexes of the type
(IP6)Hx(Spm). The IP6 protonation constants, stability constants of the adducts and equilibrium constants of
their formation have been determined. The interactions between phytic acid and polyamines have ion-ion
character and the charge is the main factor determining their effectiveness, although the structure of polyamines
should be also taken into account. Unexpectedly, it has been found that the effectiveness of the noncovalent
interactions with phytic acid is greater for the derivatives of biogenic amines than for the amines occurring in
living organisms. In contradistinction to molecular complexes of polyamines with nucleotides, the stability of the
complexes formed with phytic acid decreases with increasing length of amine chain.
References:
[1] B.F. Harland, G. Narula, Nutr. Res., 19 (1999) 633
[2] G. Urbano, M. Lopez-Jurado, P. Aranda, C. Vidal-Valverde, E. Tenorio, J. Porres, J. Physiol. Biochem., 56
(2000) 283
[3] C.W. Tabor, H. Tabor, Ann. Rev. Biochem., 53 (1984) 749
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