Influence of sulphide, selenide and lead ions on the activity of delta-aminoleavulinic acid dehydratase in blood of experimental animals in vitro

In the present reasearch the influence of chemical analogues – sulphide (S2-) and selenide (Se2-) ions - on the activity of δ-aminoleavulinic acid dehydratase (δ-ALAD) in bovine blood in vitro upon impact of lead ions (Pb2+) was investigated. It was shown that high concentrations of Se2- inhibited the activity of enzyme δ-ALAD in vitro in higher extent compared to equimolar concentrations of S2- . The leap of enzyme activity inhibition occurred under the lower concentrations of Se2- in comparison to S2-. The shift of the leap of the inhibition of δ-ALAD activity under the impact of Pb2+ ions depended on the S2- concentration as follows: Pb2+ ions inhibited the enzyme activity faster in the absence of S2- if compared to the presence of low substantial active concentration of S2- ions. The S2- ions had the protective properties on the enzyme activity in vitro since the δ-ALAD activity was not inhibited completely even at high concentration of the S2- ions. The addition of Se2- ions to the bovine blood acted similarly to S2- ions and slowed down the lead hazardous impact on the enzyme’s activity. It showed that Se2- ions as well as S2- ions had protective properties in vitro. The comparison of protective properties revealed that the activity of δ-ALAD activity upon impact of lead ions decreased in less extent in the presence of Se2- ions if compared to the presence of S2- ions. Although both anions are characterized by the protective activity in vitro, the protective activity of Se2- anions was higher than of S2-. The investigations showed that the effects of the ions on blood δ-ALAD activity can be foreseen, compared and evaluated in vitro according to the impulse of the leap of enzyme inhibition (concentration value of the catalytic poison, which corresponds to half-leap of the enzyme inhibition)