Effect of Some Physiological Conditions on Chromohalobacter sp. İsolate's δAminolevulinic Acide Dehydratase (ALAD)

Abstract

Saline environments are frequently contaminated with heavy metals as a result of industrial or agricultural activities. Heavy-metal
pollution represents an important environmental problem due to the toxic effects and their accumulation throughout the food chain leads to
serious ecological and health problems. Lead (Pb) is one of the most widely used metals in industries and exposure to Pb continues to be a
common problem almost in all over the world. δ-Aminolevulinic acide dehydratase (ALAD; E.C. 4.2.1.24) is a metalloprotein and plays a
crucial role in heme synthesis. The inhibition of the enzyme δ-aminolevulinic acid dehydratase is recognized as a useful biomarker of Pb
exposure and effect, both in humans and other animal species. Selective inhibition of ALAD with lead is an important biological marker of
chemical contamination. In this study the effects of some heavy metals on ALADs activity of Chromohalobacter sp. isolates has been
studied in order to determine whether their ALADs could be used as biosensor for lead and other heavy metals contamination.
Spektrofotometric method was used to determine ALADs activity. According to the results, Pb negatively effected ALADs activity of
Chromohalobacter sp. isolates. Some heavy metals inhibited its activity ratio of Pb(NO3)2 %15, ZnSO4 %38, MnCl2 %54, CoCl2 %36,
FeSO4 %15, Ni(NO3)2 %52. Surprisingly, MnSO4 increased its activity up to 8%. ALAD activity was observed at pH between 3 and 11,
optimum pH was found to be 5 and it was observed that ALAD has an optimal temperature between 20 and 37 °C.