is a nucleoside
attached to a ribose
) ring via a β-N9
Guanosine can be phosphorylated to become GMP (guanosine monophosphate), cGMP (cyclic guanosine monophosphate), GDP (guanosine diphosphate) and GTP (guanosine triphosphate).
When guanine is attached to a deoxyribose ring, it is known as a deoxyguanosine.