4-Hydroxy-alkenals interaction with purified microtubular protein.

4-Hydroxy-alkenals effect on microtubular system has been investigated, comparing the activity of both biogenic and non-biogenic aldehydes. As these aldehydes react essentially with sulphydryl groups, their action on titratable thiol groups microtubular protein was studied. These compounds evidenced an inhibitory effect on this parameter and on tubulin polymerization, where sulphydryls are essential. 4-Hydroxy-alkenals inhibit tubulin polymerization in a dose-dependent manner (0.1-1 mM), with the exception of 4-hydroxy-octenal, that shows an inhibitory action only in concentrations from 0.5 mM up. Its behaviour is very anomalous: in fact the tubulin-colchicine binding, is stimulated rather than inhibited, whereas such binding is inhibited by the other tested aldehydes. Our present results give then a support for an interaction between 4-hydroxy-alkenals and microtubular protein.