PARENT SESSION
8A CICTA2001
9:00 AM to 7:00 PM, Wednesday, 09 May 2001

(W/FF242) In vitro inhibition of several MFO-associated reductase activities by heavy metals in Paracentrotus lividus, Lmk.

Montero Torreiro, M.¹, Garcia Martinez, P.¹, ¹

ABSTRACT- The mixed-function oxygenase (MFO) system present in marine animals has been widely considered as a potential biomarker for organic pollution in the sea. However, the inhibition that heavy metals produce in MFO system has not been always considered. For this reason, the aim of the present study is to evaluate the in vitro effects of Cu⁺², Cd⁺², Hg⁺² and Pb⁺² on the MFO-associated reductase activities from the gonads of Paracentrotus lividus. Four different reductase activities related to the MFO system were analysed, viz NAD(P)H-cytochrome c reductase (cytcred) and NAD(P)H-ferricyanide reductase (ferrired). Addition to the reaction mixture of different concentrations of those heavy metals showed inhibition of the enzymes. Such inhibition was total in the presence of 25, 100 and 200 g/ml for Hg⁺², Cu⁺² and Pb⁺², respectively. However, the concentration of Cd⁺² that produced total inhibition was higher for cytcred (100 g/ml) than for ferrired (25 g/ml). Therefore, it is important to evaluate the influence of heavy metals in the MFO system of marine animals before its use as biomarker of organic pollution.

Key words: Paracentrotus lividus, MFO system, In vitro inhibition, heavy metals