Binding of deoxy-thymidine-5′-triphosphate and deoxyadenosine-5′-triphosphate to chrysotile asbestos
TRITIATED DEOXYTHYMIDINE-5′-TRIPHOSphate ([3H]dTTP) and deoxyadenosine-5′-triphosphate ([3H]dATP) were found to bind strongly to fibres of chrysotile asbestos. Binding of both triphosphates to amosite and crocidolite, however, was much less than that to chrysotile. Further work with chrysotile showed that the binding appears to be electrostatic in nature, with the negative phosphate groups of the nucleotides attaching to the positively charged groups on the mineral fibre. Attachment of the triphosphates to the mineral surface was found to be concentration dependent. Time curves of binding indicated that, for both nucleoside triphosphates, binding was rapid at 20°C and 37°C. Strong binding was also observed at 55°C. Binding at the higher temperatures depended on the type of buffer used and pH. Bound [3H]dTTP and [3H]dATP could be partially removed from chrysofile by 0.1 M sodium pyrophosphate after a short incubation at 20°C. Various chemical reagents that affected binding were studied and are discussed. The possible use of chrysotile asbestos as a solid phase material for the polymerization of dTTP and dATP or activated 5′-phosphorimidazolide of adenosine is also discussed.