The Effect of pH and Ionic Strength on Rate of Reaction of Plasma Albumin with Formaldehyde in Water Solution and Ethanol-Water Binary Mixtures

Ugye, Uzairu, Idris, Kwanashie
2013 International Journal of Research in Chemistry and Environment   unpublished
The effects of pH and ionic strength on the rate of reaction of plasma albumin with formaldehyde in water and 15%ethanol-water system were investigated in the pH range of 5.3-8.7 and neutral salt range 0.1-0.9 moldm-3 NaCl. The rate constants for the reaction in water medium have been found to increased with increase in pH. This has been observed to be similar with an analogous aldehyde, glutaraldehyde whose reactions with proteins increased with in increase in pH This behaviour is reported to
more » ... ndicate non protonation of the adduct formed between formaldehyde and the plasma albumin at higher pHs. Similarly, the rate constants of the reaction in 15% Ethanol-water mixture increased with increase in pH though not in a smooth fashion and the same reason could be ascribed to this system too. In addition it could be asserted that changes in the internal structure of medium on addition of ethanol does have an effect on the reaction rate. The results of the effects of ionic strength on the reaction in water solution show that there was a linear rate dependence on the ionic strength of medium and the rate increased with increase in the ionic strength of the salt. The values of rate constants in ethanol solution were found to increased with the increase in ionic strength and concentration of ethanol, this deviation from the Bronsted theory is in accordance with the literature. The reason for such behaviour is reported to be due to the greater influence of ionic orientation for regulating the reaction velocity. Favourable ionic interactions have been found to be important for binding of biomolecular species. The result also point to the major contributions of buffer solutions to the reactions of neutral species.