Publications of Alessandro Bertuzzi

This page shows all publications that appeared in the IASI annual research reports. Authors currently affiliated with the Institute are always listed with the full name.

You can browse through them using either the links of the following line or those associated with author names.

Show all publications of the year  1994, with author Bertuzzi A., in the category IASI Research Reports (or show them all):


IASI Research Report n. 380  (Previous    Next)


Gandolfi A., Mingrone G., Bertuzzi A., Greco A.V., Vanholder R., Ringoir S.

Binding of L-tryptophan to human serum albumin and competition with indole-3-acetic acid

ABSTRACT
The level of free tryptophan and its metabolities in serum appears to be related to some pathologic states, such as chronic renal failure and neuropsychiatric disords, so that a precise characterization of tryptophan binding to serum albumin is of interest. In the present paper, the binding of L-tryptophan to defatted human serum albumin at 37?C and pH 5, 7.4, and 8.5 was studied by means of equilibrium dialysis. In addition, the competition between L-tryptophan and indole-3-acetic acid was investigated at pH 7.4, as well as the binding of L-tryptophan in human serum. We found for the binding to defatted albumin one site with association constant 1.04 x 10^4 M^-1 at pH 7.4, and 0.52 sites per albumin molecule with association constant 10.59 x 10^4 M^-1 at pH 8.5. Negligible binding was found at pH 5. The competition experiment suggested that one specific site on albumin is common for L-tryptophan and indole-3-acetic acid, but the data were not adequately predicted by a purely competitive scheme. An alternative scheme, in which the binding of indole-3-acetic acid to a site different from the common site inhibits tryptophan binding, gave a better prediction of data. The experiments performed in serum showed a mild reduction of binding with respect to experiments with defatted albumin. This reduction appears be due to a decrease of the number of available binding sites more than to a decrease of their affinity.
back
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -