Berens R L, Marr J J, LaFon S W, Nelson D J
Mol Biochem Parasitol. 1981 Jul;3(3):187-96. doi: 10.1016/0166-6851(81)90049-9.
Culture forms of Trypanosoma cruzi are incapable of synthesizing purines de novo from formate, glycine, or serine and require an exogenous purine for growth. Adenine, hypoxanthine, guanine, xanthine and their respective ribonucleosides are equal in their abilities to support growth. Radiolabeled purine bases, with the exception of guanine, are stable and are converted to their respective ribonucleotides directly by phosphoribosyltransferase activity. Guanine is both converted to its ribonucleotide and deaminated to xanthine. Purine nucleosides are not hydrolysed to any extent but are converted to their respective ribonucleotides. This conversion may involve a rete-limiting ribonucleoside cleaving activity or a purine nucleoside kinase or phosphotransferase activity. The apparent order of salvage efficiency for the bases and their respective ribonucleosides is adenine greater than hypoxanthine greater than guanine greater than xanthine.
克氏锥虫的培养形式无法利用甲酸、甘氨酸或丝氨酸从头合成嘌呤，生长需要外源性嘌呤。腺嘌呤、次黄嘌呤、鸟嘌呤、黄嘌呤及其各自的核糖核苷支持生长的能力相同。除鸟嘌呤外，放射性标记的嘌呤碱是稳定的，可通过磷酸核糖基转移酶活性直接转化为各自的核糖核苷酸。鸟嘌呤既转化为其核糖核苷酸，又脱氨生成黄嘌呤。嘌呤核苷在任何程度上都不会被水解，但会转化为各自的核糖核苷酸。这种转化可能涉及限速的核苷裂解活性或嘌呤核苷激酶或磷酸转移酶活性。碱基及其各自核糖核苷的补救效率的明显顺序是腺嘌呤大于次黄嘌呤大于鸟嘌呤大于黄嘌呤。
