Marr J J, Berens R L, Nelson D J
Biochim Biophys Acta. 1978 Dec 1;544(2):360-71. doi: 10.1016/0304-4165(78)90104-6.
We have studied purine metabolism in the culture forms of Leishmania donovani and Leishmania braziliensis. These organisms are incapable of synthesizing purines de novo from glycine, serine, or formate and require an exogenous purine for growth. This requirement is better satisfied by adenosine or hypoxanthine than by guanosine. Both adenine and inosine are converted to a common intermediate, hypoxanthine, before transformation to nucleotides. This is due to the activity of an adenine aminohydrolase ((EC 3.5.4.2), a rather unusual finding in a eukaryotic cell. There is a preferential synthesis of adenine nucleotides, even when guanine or xanthine are used as precursors. The pathways of purine nucleotide interconversions in these Leishmania resemble those found in mammalian cells except for the absence of de novo purine biosynthesis and the presence of an adenine-deaminating activiting.
我们研究了杜氏利什曼原虫和巴西利什曼原虫培养形式中的嘌呤代谢。这些生物体无法从甘氨酸、丝氨酸或甲酸从头合成嘌呤，生长需要外源性嘌呤。腺苷或次黄嘌呤比鸟苷更能满足这一需求。腺嘌呤和肌苷在转化为核苷酸之前都会转化为共同的中间体次黄嘌呤。这是由于腺嘌呤氨基水解酶（(EC 3.5.4.2)）的活性，这在真核细胞中是一个相当不寻常的发现。即使使用鸟嘌呤或黄嘌呤作为前体，也会优先合成腺嘌呤核苷酸。这些利什曼原虫中的嘌呤核苷酸相互转化途径与哺乳动物细胞中的相似，只是没有嘌呤从头生物合成且存在腺嘌呤脱氨基活性。
