The Effects of 1-Propanol on Behaviour of Human Serum Albumin in Alkaline Solution

Abstract

The effects of 1-propanol ant to a certain extent of ethanol on human serum albumin were studied over the pH range 7 - 13.3 and alcohol concentrations up to 20 vol.%. In some case behaviour of the native preparation was compared with albumin cleared of weaker bound fatty acids. The data obtained by UV-spectrophotometry were discussed from the point of view of individual types of chromophores as well as in a broader context of the secondary structure. The results can be summarized as follows: (a) Partial removal of bound fatty acids has an influence on the dissociation of tyrosines. (b) The effect of alcohols on this dissociation is rather complex, the permitivity of the solvent being only a part of it. (c) At high alkaline pH a series of peaks in the fourth-derivative absorption spectra appear in the region 305 - 320 nm. These peaks were shown to correspond to buried dissociated tyrosines. (d) In the presence of 1-propanol a small conformational transition of albumin molecule is observed at pH below 9.