A novel nucleoside prodrug-activating enzyme: Substrate specificity of biphenyl hydrolase-like protein
A novel nucleoside prodrug-activating enzyme: Substrate specificity of biphenyl hydrolase-like protein
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DOI：
10.1021/mp0499757
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发表时间：
2004-03-01
影响因子：
4.9
通讯作者：
Amidon, Gordon L.
中科院分区：
文献类型：
--
作者：
Kim, Insook;Song, Xueqin;Amidon, Gordon L.
联苯水解酶样蛋白（Biphenyl hydrolase-like protein，BPHL）是一种新的丝氨酸水解酶，最近被鉴定为人伐昔洛韦酶（valacyclovirase），催化抗病毒药物伐昔洛韦和缬更昔洛韦的水解活化。用一系列治疗性核苷类似物的氨基酸酯前药研究BPHL的底物特异性：阿昔洛韦、齐多夫定、阿糖胞苷、2-溴-5，6-二氯-1-（β-D-呋喃核糖基）苯并咪唑和吉西他滨。研究了BPHL对典型酯酶和氨肽酶底物的水解。结果表明，BPHL的底物特异性主要由氨基酸酰基前体决定，对核苷类母体药物不敏感。对于所有核苷母体药物，BPHL优选疏水性氨基酸缬氨酸、苯丙氨酸和脯氨酸，而不是带电氨基酸赖氨酸和天冬氨酸。前药的位置和单酯或二酯形式也很重要，BPHL对5 ′-酯的亲和力高于对3 ′-酯和31，5 ′-二酯的亲和力，与氨基酸类型无关。此外，3 ′-氨基酸酯的存在显著降低了5 ′-氨基酸酯官能团的水解速率。BPHL对5 ′-缬氨酰尿苷和5 ′-苯丙氨酰尿苷的L/D特异性比分别为32和1.5。底物特异性表明BPHL的底物结合口袋具有疏水酰基结合位点，其可以容纳带正电荷的α-氨基，同时具有醇离去基团结合位点，其可以容纳具有相对慷慨的空间允许的核苷类似物。总之，除了伐昔洛韦和缬更昔洛韦之外，BPHL催化宽范围的治疗性核苷类似物的氨基酸酯的水解活化，并且具有相当大的用作设计抗病毒和抗癌核苷类似物前药的活化靶标的潜力。
Biphenyl hydrolase-like protein (BPHL, NCBI accession number NP_004323) is a novel human serine hydrolase recently identified as a human valacyclovirase, catalyzing the hydrolytic activation of the antiviral prodrugs valacyclovir and valganciclovir. The substrate specificity of BPHL was investigated with a series of amino acid ester prodrugs of the therapeutic nucleoside analogues: acyclovir, zidovudine, floxuridine, 2-bromo-5,6-dichloro-1-(beta-D-ribofuranosyl) benzimidazole, and gemcitabine. The hydrolysis of typical esterase and aminopeptidase substrates by BPHL was also investigated. The results indicate that the substrate specificity of BPHL is largely determined by the amino acid acyl promoiety, and is less sensitive to the nucleoside parent drugs. For all nucleoside parent drugs, BPHL preferred the hydrophobic amino acids valine, phenylalanine, and proline over the charged amino acids lysine and aspartic acid. The position and monoester or diester form of the prodrug were also important, with BPHL exhibiting higher affinity for the 5'-esters than for the 3'-esters and the 31, 5'-diesters irrespective of amino acid type. Further, the presence of the 3'-amino acid ester considerably reduced the hydrolysis rate of the 5'-amino acid ester functionality. BPHL exhibited stereoselectivity with an L/D specificity ratio of 32 for 5'-valyl floxuridine and 1.5 for 5'-phenylalanyl floxuridine. The substrate specificity suggests that the substrate-binding pocket of BPHL has a hydrophobic acyl binding site which can accommodate the positively charged alpha-amino group, while having an alcohol leaving group binding site that can accommodate nucleoside analogues with a relatively generous spatial allowance. In conclusion, BPHL catalyzes the hydrolytic activation of amino acid esters of a broad range of therapeutic nucleoside analogues in addition to valacyclovir and valganciclovir and has considerable potential for utilization as an activation target for design of antiviral and anticancer nucleoside analogue prodrugs.