Indexed on: 01 Jul '96Published on: 01 Jul '96Published in: BioMetals
This study demonstrates a pH-dependent inhibition of Mg2+- and Ca2+- ATPase activities ofNostoc linckia andChlorella vulgaris exposed to AlCl3, AlF3, NaF and AlCl3 + NaF together. AlF3 and the combination of AlCl3 + NaF were more inhibitory to both the enzymes as compared with AlCl3 and NaF. Toxicity of the test compounds increased with increasing acidity. Interaction of AlCl3 + NaF was additive onN. linckia andC. vulgaris, respectively, at pH 7.5 and 6.8, and synergistic at pH 6.0 and 4.5. In the presence of 60 and 100μm PO43- an increased NaF concentration (in the AlCl3 + NaF combination) was required to produce the same degree of inhibition in ATP synthesis and ATPase activity. Toxicity of fluoroaluminate was reduced in the presence of EDTA and citrate. Except for beryllium to some extent, combinations of cadmium, cobalt, iron, manganese, tin and zinc with fluoride were not as effective as aluminium in inhibiting the ATPase activity. The presence of a 100 kDa protein band in SDS-PAGE of both control as well as AlCl3 + NaF-treated samples suggested that AlF4− inhibits the ATPase activity by acting as a functional barrier without affecting the structure of the enzyme.