Catabolism of exogenous deoxyinosine in cultured epithelial amniotic cells

Uptake and catabolism of purine nucleosides have been commonly considered a s means to salvage the purine ring for nucleic acid synthesis, usually negl ecting the destiny of the pentose moiety. With the aim to ascertain if deox yribose derived from exogenous DNA can be utilised as a carbon and energy s ource, we studied the catabolisin of exogenous deoxyinosine in a cell line derived from human amnion epithelium (WISH). Intact WISH cells catabolise d eoxyinosine by conversion into hypoxanthine. The nucleoside enters the cell through a nitrobenzylthioinosine-insensitive equilibrative transport. Deox yinosine undergoes a phosphorolytic cleavage inside the cell. The purine ba se diffuses back to the external medium, while the phosphorylated pentose m oiety can be further catabolised to glycolysis and citric acid cycle interm ediates. Our results indicate that the catabolism of the deoxynucleoside ca n be considered mainly as a means to meet the carbon and energy requirement s of growing cells. (C) 2001 Elsevier Science B.V. All rights reserved.