人五毛滴虫：嘌呤补救途径。

Pentatrichomonas hominis: purine salvage pathway.

Tang P, Lo H S

Department of Parasitology and Tropical Medicine, National Defense Medical Center, Taipei, Taiwan, Republic of China.

Comp Biochem Physiol B. 1988;90(2):419-25. doi: 10.1016/0305-0491(88)90098-3.

Abstract

Pentatrichomonas hominis was found incapable of de novo synthesis of purines. 2. Pentatrichomonas hominis can salvage adenine, guanine, hypoxanthine, adenosine, guanosine and inosine, but not xanthine for the synthesis of nucleotides. 3. HPLC tracing of radiolabelled purines or purine nucleosides revealed that adenine, adenosine and hypoxanthine are incorporated into adenine nucleotides and IMP through a similar channel while guanine and guanosine are salvaged into guanine nucleotides via another route. There appears to be no direct interconversion between adenine and guanine nucleotides. Interconversion between AMP and IMP was observed. 4. Assays of purine salvage enzymes revealed that P. hominis possess adenosine kinase; adenosine, guanosine and inosine phosphotransferases; adenosine, guanosine and inosine phosphorylases and AMP deaminase.

摘要

发现人五毛滴虫无法从头合成嘌呤。2. 人五毛滴虫能够利用腺嘌呤、鸟嘌呤、次黄嘌呤、腺苷、鸟苷和肌苷来合成核苷酸，但不能利用黄嘌呤。3. 对放射性标记的嘌呤或嘌呤核苷进行高效液相色谱追踪显示，腺嘌呤、腺苷和次黄嘌呤通过相似途径掺入腺嘌呤核苷酸和肌苷酸，而鸟嘌呤和鸟苷则通过另一条途径被挽救进入鸟嘌呤核苷酸。腺嘌呤核苷酸和鸟嘌呤核苷酸之间似乎没有直接的相互转化。观察到了腺苷酸和肌苷酸之间的相互转化。4. 嘌呤补救酶的测定表明，人五毛滴虫拥有腺苷激酶；腺苷、鸟苷和肌苷磷酸转移酶；腺苷、鸟苷和肌苷磷酸化酶以及腺苷酸脱氨酶。