Cyanate inhibition of erythrocyte glucose-6-phosphate dehydrogenase.

Abstract

IT has been suggested that cyanate (CNO) may be useful as a therapeutic agent in the prevention of occlusive sickle cell crises1. Cyanate irreversibly carbamylates the N-terminal amino (NH2) groups of proteins and the free epsilon −NH2 groups of lysine2. Carbamylation of the terminal valine residue of sickle haemoglobin is thought to be responsible for preventing affected red blood cells (RBCs) from sickling when they are deoxygenated1. Sickle cell erythrocytes incubated with 50 mM cyanate for 90 min in vitro reportedly have an increased survival when they are radiolabelled and reinfused into the donor3. This report describes a possible side-effect of RBCs treated in vitro with sodium cyanate in similar experimental conditions: there is irreversible inactivation of the enzyme glucose-6-phosphate dehydrogenase (G6PD).