Paglia D E, Valentine W N, Nakatani M, Brockway R A
Department of Pathology and Laboratory Medicine, University of California, Los Angeles 90024.
Blood. 1989 Nov 1;74(6):2161-5.
Erythrocytes from 11 patients with presumptive diagnoses of transient erythroblastopenia of childhood were evaluated retrospectively (six) or prospectively (five) for a possible relationship between erythrocyte adenosine 5'-monophosphate aminohydrolase, adenylic acid deaminase (AMP deaminase) activity and intracellular concentrations of adenine nucleotides. Older red blood cell (RBC) cohorts in these patients consistently exhibited significantly decreased activities of AMP deaminase (approximately 5% to 70% of normal control mean) in association with increased concentrations (up to threefold) of adenosine triphosphate (ATP) and total adenine nucleotides. We postulate that the latter is a direct consequence of the former, since diminishing AMP deaminase activity in aging cells should reduce the drain on the adenine nucleotide pool imposed by irreversible deamination of AMP to inosine 5'-monophosphate. Consistent reductions in AMP deaminase activity indicate that this enzyme should also serve as a reliable marker of mean RBC age useful in diagnostic confirmation of transient erythroblastopenia. The observed increases in ATP and total adenine nucleotides in older RBCs require a reevaluation of the traditional view that age-related losses of these compounds mediate the ultimate demise of senescent erythrocytes. Similar alterations in the balance of degradative and salvage pathways in RBC nucleotide metabolism may also underlie certain cases of so-called "high ATP syndrome."
对11例初步诊断为儿童暂时性红细胞生成减少症的患者的红细胞进行了回顾性（6例）或前瞻性（5例）评估，以探讨红细胞腺苷5'-单磷酸氨基水解酶、腺苷酸脱氨酶（AMP脱氨酶）活性与腺嘌呤核苷酸细胞内浓度之间可能存在的关系。这些患者中较老的红细胞（RBC）群体始终表现出AMP脱氨酶活性显著降低（约为正常对照平均值的5%至70%），同时三磷酸腺苷（ATP）和总腺嘌呤核苷酸浓度升高（高达三倍）。我们推测，后者是前者的直接结果，因为衰老细胞中AMP脱氨酶活性的降低应会减少由于AMP不可逆脱氨生成5'-单磷酸肌苷而对腺嘌呤核苷酸池造成的消耗。AMP脱氨酶活性的持续降低表明，该酶也应作为平均RBC年龄的可靠标志物，有助于儿童暂时性红细胞生成减少症的诊断确认。在较老的RBC中观察到的ATP和总腺嘌呤核苷酸增加，需要重新评估传统观点，即这些化合物与年龄相关的损失介导了衰老红细胞的最终死亡。RBC核苷酸代谢中降解途径和补救途径平衡的类似改变也可能是某些所谓“高ATP综合征”病例的基础。
