INTERACTIONS OF H- STUDY BY FACTOR-ANALYSIS( AND CU(II) IONS WITH POLY(ADENYLIC ACID) )

The interactions of H+ and Cu(II) ions with poly(adenylic acid) (polyA ) are investigated using different factor analysis techniques. From th e changes in the ultraviolet and circular dichroism absorption spectra obtained in the course of spectroscopic acid-base titrations of poly( adenylic acid) solutions containing different amounts of Cu(II) ion, t he unitary spectra, the concentrations, and the stabilities of the mac romolecular species detected are estimated. Four spectroscopically dif ferent species are detected for poly(adenylic acid) in the pH interval 1.5-6.8. Three of them are different conformations of the protonated form of polyA, and the other is the unprotonated form of polyA. One ne w species is detected in the presence of Cu(II) ion.