Phosphate buffer and salt medium concentrations affect the inactivation of T4 phage by platinum(II) complexes

The initial rate of inactivation of T4 phage by solutions of [Pt(NH3)2Cl2], [PtenCl2] and [Pten(H2O)2] (NO3)2 at fixed values of pH is strongly reduced by phosphate buffer, slightly reduced by acetate buffer and apparently not influenced by bis(2-hydroxyethyl)aminotris(hydroxymethyl)methane (BIS-Tris) buffer and HEPES buffer. The phosphate abolishes the antiphage activity of the platinum complexes probably by some sort of complex formation. This together with dimerization reactions qualitatively explains the tailing off of the phage inactivation rate. High concentrations of NaNO3 as the salt medium give increased phage inactivation rates, which are also strongly pH-dependent.