Metachromasia and Circular Dichroism induced by ATP and ADP : Evidence in Favour of Bent Phosphate Chain

Department of Bio-Chemistry & Bio-Physics, University of Kalyani, Kalyani-741 235 Manuscript received 29 August 1991, revised 8 April 1992, accepted 7 April 1992 ATP, ADP and AMP bind the dye pinacyanol chloride stoichiometrically. Broad and multiple banded metachromasia are induced by ATP and ADP, but not by AMP. Thus ATP and ADP are the smallest chromotropes to induce metachromasia in the dye These two compounds also induce strong dichroism in pinacyanol resolvable into three biphasic components corresponding to the observed bands in the metachromatic spectra. This induction of CD in the dye has been interpreted from the bent conformation of the phosphate chain, and not directly from the chiral deoxyribose moiety