GTPn.（名词）A nucleotide composed of guanine, ribose, and three phosphate groups and necessary for the synthesis of RNA.三磷酸鸟苷：由鸟嘌呤、核酸和三组磷酸盐组成的核苷核酸，为合成核糖核酸的必备成分来源：g(uanosine) t(ri)p(hosphate) g(uanosine) t(ri)p(hosphate)
