Study of interactions between actinomycin D and DNA on carbon paste electrode (CPE) and on the hanging mercury drop (HMDE) surface I.Ch. Gherghi b,1 , S.T. Girousi a, *, A.N. Voulgaropoulos a , R. Tzimou- Tsitouridou b a Department of Chemistry, Analytical Chemistry Laboratory, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece b Department of Chemical Engineering, Analytical Chemistry Laboratory, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece Received 30 August 2002; received in revised form 28 November 2002; accepted 28 November 2002 Abstract The interaction of actinomycin (ACTD) with double stranded (ds) calf thymus DNA and single stranded (ss) DNA was studied at the carbon paste electrode surface by means of transfer voltammetry in 0.2 M phosphate buffer solution (pH 7.4). Accordingly the interaction of actinomycin (ACTD) with ds calf thymus DNA, ss DNA and supercoiled (sc) DNA was studied using hanging mercury drop electrode in 0.3 M NaCl, and 50 mM sodium phosphate buffer (pH 8.5). The different electrochemical behaviours are presented and compared in the article. # 2002 Elsevier Science B.V. All rights reserved. Keywords: Actinomycin-D; DNA intercalators; CPE; HMDE 1. Introduction Actinomycin D (ACTD) is an antitumor anti- biotic that contains a 2-aminophenoxazin-3-one chromophore and two cyclic pentapeptide lac- tones. This drug has been used clinically for the treatment of highly malignant tumors and also in combination with other antitumor agents to treat high-risk tumors [1,2]. There is general agreement that its antitumor activity is directly attributable to its ability to bind within duplex DNA via intercalation of the planar chromophore, preferably at the GpC sequence with the two pentapeptide rings resting on the * Corresponding author. Tel.:  /30-31-0997722; fax:  /30- 31-0997719. E-mail address: girousi@chem.auth.gr (S.T. Girousi). 1 Scholarship holder from the Greek State Scholarship Foundation. Journal of Pharmaceutical and Biomedical Analysis 31 (2003) 1065  /1078 www.elsevier.com/locate/jpba 0731-7085/02/$ - see front matter # 2002 Elsevier Science B.V. All rights reserved. PII:S0731-7085(02)00645-3