Guanosine triphosphate catabolism in human and rabbit erythrocytes: role of reductive deamination of guanylate to inosinate.

The reductive deamination of guanylate to inosinate was demonstrable but occurred at low rates in human and rabbit erythrocytes incubated in vitro with or without glucose. However, the process was considerably accelerated in erythrocytes incubated with deoxyglucose. In human erythrocytes incubated with deoxyglucose, deamination was the major pathway of catabolism of guanylate; little or no guanylate was dephosphorylated. In rabbit erythrocytes, guanylate was both deaminated and dephosphorylated. Inosinate formed from guanylate was metabolized only by dephosphorylation in human erythrocytes, but in rabbit erythrocytes, it was also converted to xanthylate.