Erythrocyte sorbitol dehydrogenase of selected non-mammalian vertebrates

Erythrocyte sorbitol dehydrogenase activity (EC 1.1.1.14) from selected non-mammalian vertebrates was studied showing great variability not related to their phylogenetical position. The Michaelis-Menten constant (Km) for sorbitol exhibited moderate low values in the studied animals. In snakes the Km for sorbitol was low with moderate activity of sorbitol dehydrogenase, suggesting that the enzyme could reach maximum activity with lower sorbitol concentration in comparison to other vertebrates. In the snakes the enzyme showed the same affinity for all the studied polyols, indicating that we are probably dealing with a very ancient enzyme, an unspecific enzyme.