Kelley J L, Linn J A, McLean E W, Tuttle J V
Division of Organic Chemistry, Burroughs Wellcome Co., Research Triangle Park, North Carolina 27709.
J Med Chem. 1993 Oct 29;36(22):3455-63. doi: 10.1021/jm00074a029.
A series of 9-[(phosphonoalkyl)benzyl]guanines was synthesized and tested for inhibition of human erythrocyte purine nucleoside phosphorylase (PNPase). Inhibitors of PNPase should be T-cell selective, immunosuppressive agents with potential clinical utility in the treatment of a wide variety of disorders in which T-lymphocytes are pathogenic. An initial set of six analogues of the weak PNPase inhibitor 9-benzylguanine (2) contained a phosphonic acid group linked to the ortho, meta, or para position of the aryl moiety via two- or three-atom spacers. These compounds allowed us to probe for a favorable interaction with the phosphate-binding domain. Several additional meta phosphonoalkyl substituents were examined in an effort to optimize the spacer. The two most potent compounds, [[3-[(2-amino-1,6-dihydro-6-oxo-9H-purin-9-yl)methyl] benzyl]oxy]-methylphosphonic acid (3f) and [[3-[(2-amino-1,6-dihydro-6-oxo-9H-purin-9-methyl)methyl] benzyl]-thio]methylphosphonic acid (3j), were inhibitors of PNPase with Ki's of 5.8 and 1.1 nM, respectively. These inhibitors displayed competitive kinetics with respect to inosine and inorganic phosphate, which showed that these compounds possess binding determinants for both the purine- and phosphate-binding domains of the enzyme, characteristics that are consistent with 3f and 3j being multisubstrate analogue inhibitors of PNPase. The potency of 9-benzylguanine (2) was enhanced more than 6000-fold by linking a phosphonic acid residue with a (methylthio)methyl spacer to the meta position of 2 to give 3j, which illustrates the potent enzyme inhibitory properties available to multisubstrate analogue inhibitors.
合成了一系列9-[(膦酰基烷基)苄基]鸟嘌呤，并测试了它们对人红细胞嘌呤核苷磷酸化酶(PNPase)的抑制作用。PNPase抑制剂应具有T细胞选择性，是具有潜在临床应用价值的免疫抑制剂，可用于治疗多种以T淋巴细胞为致病因素的疾病。弱PNPase抑制剂9-苄基鸟嘌呤(2)的最初一组六个类似物含有一个膦酸基团，该基团通过两个或三个原子的间隔基连接到芳基部分的邻位、间位或对位。这些化合物使我们能够探索与磷酸盐结合结构域的有利相互作用。为了优化间隔基，又研究了几个额外的间位膦酰基烷基取代基。两种最有效的化合物，[[3-[(2-氨基-1,6-二氢-6-氧代-9H-嘌呤-9-基)甲基]苄基]氧基]-甲基膦酸(3f)和[[3-[(2-氨基-1,6-二氢-6-氧代-9H-嘌呤-9-甲基)甲基]苄基]-硫代]甲基膦酸(3j)，是PNPase的抑制剂，其Ki值分别为5.8和1.1 nM。这些抑制剂对肌苷和无机磷酸盐表现出竞争性动力学，这表明这些化合物对该酶的嘌呤结合结构域和磷酸盐结合结构域都具有结合决定簇，这些特性与3f和3j作为PNPase的多底物类似物抑制剂一致。通过将一个带有(甲硫基)甲基间隔基的膦酸残基连接到2的间位得到3j，9-苄基鸟嘌呤(2)的效力提高了6000多倍，这说明了多底物类似物抑制剂具有强大的酶抑制特性。
