The effect of heparin and pentosan polysulfate on the thermal stability of yeast alcohol dehydrogenase.

Heparin and pentosan polysulfate as organic polyanions inhibit yeast alcohol dehydrogenase (YADH). The aim of this study was to determine the effect of heparin and pentosan polysulfate on the thermostability of alcohol dehydrogenase. Spectral and kinetic analyses showed that these compounds increase the thermal stability of the enzyme and eliminate entirely thermal aggregation. The thermostabilizing effect of unfractionated heparin and pentosan polysulfate was accelerated in the presence of NAD+. The addition of NAD+ (11 microM) to the incubation medium decreased the inhibition of the YADH activity in the presence of pentosan polysulfate (1.32 microM). Moreover, 38% of the residual activity of YADH was found after a 5-min incubation at 70 degrees C. These findings indicate that heparinoids not only modulate the enzyme activity but also can prevent the protein's thermal denaturation.