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Original
Research Article
Uptake and
kinetic properties of choline and ethanolamine in
Plasmodium falciparum
H Ahiboh1,3,
AJ Djaman2, FH Yapi2, A Edjeme-Aké1,
ML Hauhouot-Attoungbré1, ED Yayo1,
D Monnet1
1Département
de Biochimie Biologie Moléculaire, UFR des Sciences
Pharmaceutiques et Biologiques, Université de Cocody –
Abidjan BP V34 2Laboratoire de
Pharmacodynamie Biochimique - UFR de Biosciences,
Université de Cocody – Abidjan BP V34. 3Département
de Biochimie Fondamentale et Clinique – Institut Pasteur
de Côte d’Ivoire – 01 BP 490 Abidjan 01
Correspondence:
E-mail:
hugues.ahiboh@ucocody.ci
Tel.: (+225) 07 22 41
11,Fax
: (+225) 22 44 06 70
Tropical
Journal of Pharmaceutical Research, June
2008; 7(2):
953-959
Abstract
Purpose:
The asexual proliferation
of Plasmodium, inside the erythrocyte, is accompanied by
the synthesis of huge quantities of phosphatidylcholine
(PtdCho) and phosphatidylethanolamine (PtdEtn).
These needful
phospholipids for the cytoplasmic membrane of the
merozoites are provided by the precursors choline and
ethanolamine. PtdCho and PtdEtn are synthesized by the
parasite because the erythrocyte is unable to do it. In
order to assess the dynamism of the phospholipid
pathways, we aimed to investigate the respective shape
of the uptake of choline and ethanolamine by Plasmodium
falciparum.
Method:
Time-course experiments and kinetic assays were
performed respectively with fixed and ranged
concentrations of radioactively-labelled choline and
ethanolamine. The labelled-precursors were added in the
culture of P. falciparum infected-erythrocytes and the
incorporated molecules in phospholipids were measured
with a scintigraph counter.
Result:
The results showed that the incorporation of precursors
in the infected-erythrocyte occurred with a
Michaelis-Menten’s kinetic shape. According to the
maximum rate (Vmax), the pathway of
ethanolamine incorporation was faster than that of
choline. Similarly, affinity for ethanolamine was
greater than that of choline.
Conclusion:
Although PtdCho is the major phospholipid in the
membrane, this study rules out that the influx of
ethanolamine in the infected-erythrocyte, in vivo
conditions, is more dynamic than choline.
Keywords:
Plasmodium, phospholipids, kinetics, metabolism,
choline, ethanolamine |
