Yamada K A, Sherman I W
Mol Biochem Parasitol. 1981 Aug;3(4):253-64. doi: 10.1016/0166-6851(81)90056-6.
Extracts of normal duckling erythrocytes catabolized AMP to IMP, inosine and hypoxanthine; adenosine and adenine were not formed from AMP. When erythrocyte-free Plasmodium lophurae, prepared by antibody lysis, were incubated in the presence of [14C]hypoxanthine approximately 60% of the label was recovered as purine nucleotides and there was not evidence of extracellular alteration of added hypoxanthine. However, when adenosine was added to suspensions of antibody- or saponin-prepared parasites extensive conversion to inosine and hypoxanthine occurred. This conversion was found to be the result of parasite lysis with release of cytosolic purine salvage pathway enzymes; plasmodial surface membrane ecto-enzymes were not responsible for adenosine catabolism. It appears that in vivo the intracellular plasmodium utilizes the normal erythrocytic process of purine turnover to avail itself of hypoxanthine, the red cell's end product, and at the same time the parasite avoids direct competition for adenosine essential to erythrocyte survival. Since the blood plasma of infected ducklings contained increased amounts of hypoxanthine it is possible that P. lophurae also utilizes this as a purine source.
正常雏鸭红细胞提取物可将AMP分解为IMP、肌苷和次黄嘌呤；AMP不会生成腺苷和腺嘌呤。当通过抗体裂解制备的无红细胞的约氏疟原虫在[14C]次黄嘌呤存在下孵育时，约60%的标记物以嘌呤核苷酸形式回收，且没有证据表明添加的次黄嘌呤在细胞外发生了改变。然而，当向抗体或皂素制备的寄生虫悬液中添加腺苷时，会大量转化为肌苷和次黄嘌呤。发现这种转化是由于寄生虫裂解并释放出胞质嘌呤补救途径酶所致；疟原虫表面膜外酶对腺苷分解代谢无作用。看来在体内，细胞内疟原虫利用红细胞正常的嘌呤周转过程来获取次黄嘌呤，即红细胞的终产物，同时寄生虫避免与对红细胞存活至关重要的腺苷直接竞争。由于感染雏鸭的血浆中次黄嘌呤含量增加，约氏疟原虫也有可能将其用作嘌呤来源。
