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Cell Biology International (1999) 23, 579–583 (Printed in Great Britain)

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S -ADENOSYLMETHIONINE SYNTHESIS IN LEISHMANIA INFANTUM PROMASTIGOTES

R.M Reguera^a, Y Pérez‑Pertejo^a, C Ordóñez^a, J.C Cubrı́a^a, B.L Tekwani^b, R Balaña‑Fouce^a and D Ordóñez^a,f1

^aDepartamento Farmacologı́a y Toxicologı́a (INTOXCAL), Universidad de León, Campus de Vegazana s/n, 24071, León, Spain
^bDivision of Biochemistry, Central Drug Research Institute (CDRI), Lucknow, 226001, India

Abstract

Methionine adenosyltransferase (MAT), S -adenosylmethionine (AdoMet), and S -adenosylhomocysteine (AdoHcy), have been analysed at different time-points during the growth curve of Leishmania infantum. MAT activity and AdoMet content peaked in the lag and early log phases, whereas higher levels of AdoHcy were found in stationary phase cells. MAT activity of cell extracts displayed hyperbolic kinetics for both its substrates, l -methionine and ATP, with km values of 35μm and 5m m, respectively. MAT has an absolute requirement for divalent cations, and is dependent on sulfydryl protective agents. Unlike other sources, L. infantum MAT activity seems to be transcriptionally regulated, with an accumulation of MAT-mRNA during rapid growth periods of promastigotes.

Key words: S -adenosylmethionine synthetase, Leishmania, Trypanosomatidae, polyamines, chemotherapy.

^f1To whom correspondence should be addressed: David Ordóñez Escudero, Dept. Farmacologı́a y Toxicologı́a (INTOXCAL), Universidad de León (ULE), Campus de Vegazana s/n, 24071 León, Spain. E-mail:dftrbf@isidoro.unileon.es

Received 5 January 1999; accepted 15 May 1999