Valentine W N, Paglia D E, Clarke S, Morimoto B H, Nakatani M, Brockway R
Proc Natl Acad Sci U S A. 1985 Oct;82(19):6682-6. doi: 10.1073/pnas.82.19.6682.
Ordinarily packaged in DNA, adenine deoxyribonucleotides are preferentially concentrated in erythrocyte and lymphocyte cytosol in adenosine deaminase (adenosine aminohydrolase, EC 3.5.4.4) deficiency. A spectrum of cytosol enzyme activities are defined in terms of reaction velocities, K0.5s, and nucleotide partition after incubation with ribo- and deoxyribonucleotides. AMP and dAMP were dephosphorylated, but only AMP was deaminated in vitro. Although nucleotidase activity is much stronger in lymphocytes, AMP deaminase was the dominant degradative reaction in all erythrocyte and lymphocyte lysates under the conditions specified. For most cytosolic enzymes, ribonucleotides were preferred cofactors, implying that dADP and dATP often may be bystanders at metabolic events. The adenylate kinase-mediated partition of approximately equimolar ribo- and deoxyribonucleotide substrates yielded a very large preponderance of AMP in the monophosphate compartment, the monophosphates alone being directly vulnerable to degradative loss. The adenylate kinase(s) of lymphocytes differed strikingly from those of erythrocytes in reaction velocities with nucleotide cofactors, K0.5s, and in susceptibility to substrate inhibition.
通常情况下，腺嘌呤脱氧核苷酸包装在DNA中，在腺苷脱氨酶（腺苷氨基水解酶，EC 3.5.4.4）缺乏时，优先集中在红细胞和淋巴细胞的胞质溶胶中。一系列胞质溶胶酶活性根据反应速度、K0.5值以及与核糖核苷酸和脱氧核糖核苷酸孵育后的核苷酸分配来定义。AMP和dAMP发生了去磷酸化，但体外只有AMP发生了脱氨反应。尽管核苷酸酶活性在淋巴细胞中要强得多，但在规定条件下，AMP脱氨酶是所有红细胞和淋巴细胞裂解物中的主要降解反应。对于大多数胞质溶胶酶来说，核糖核苷酸是更优的辅因子，这意味着dADP和dATP在代谢事件中往往可能只是旁观者。腺苷酸激酶介导的大约等摩尔的核糖核苷酸和脱氧核糖核苷酸底物的分配，在单磷酸区室中产生了非常大量的AMP优势，仅单磷酸酯就直接容易发生降解损失。淋巴细胞的腺苷酸激酶在与核苷酸辅因子的反应速度、K0.5值以及对底物抑制的敏感性方面与红细胞的腺苷酸激酶有显著差异。
