Proteolytic Conversion of Xanthine Dehydrogenase from the NAD-dependent Type to the 02-dependent Type
Proteolytic Conversion of Xanthine Dehydrogenase from the NAD-dependent Type to the 02-dependent Type
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黄嘌呤脱氢酶从 NAD 依赖性型向 02 依赖性型的蛋白水解转化
DOI：
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发表时间：
2001
期刊：
影响因子：
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通讯作者：
Takeshi Nishinon
中科院分区：
文献类型：
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作者：
Y. Amaya;Ken;M. Satoo;K. Noda;T. Nishino;Takeshi Nishinon
通过cDNA和纯化酶的序列分析确定了大鼠肝黄嘌呤脱氢酶(EC 1.1.1.204)的一级结构。该酶由 1,319 个氨基酸残基组成，计算分子量为 145,034 Da，包括起始甲硫氨酸，与先前报道的果蝇酶同源（Lee, C. S.、Curtis, D.、McCarron, M.、Love, C.、Gray, M.、Bender, W. 和 Chovnick, A. (1987) Genetics 116， 55-66；Keith, T. P.、Riley, M. A.、Kreitman, M.、Lewontin, R. C.、Curtis, D. 和 Chambers, G. (1987) Genetics 116, 67-73)，同一性为 52%。该酶最初以 NAD 依赖性类型存在于新鲜制备的样品中。当纯化的NAD依赖性型酶用胰蛋白酶消化时，它被切割成分子量为20、40和85kDa的三个片段，并且不可逆地转变为OS依赖性型。将三个肽片段的氨基末端序列与cDNA推导的序列进行比较表明，20-、40-和85kDa肽片段分别对应于酶的1-184、185-539和540-1319的残基。鸡酶的 5'-对氟磺酰基苯甲酰基腺苷标记肽序列的比较（Nishino, T. 和 Nishino, T. (1989) J. Biol. Chem. 264，5468-5473）揭示了 NAD 结合位点与酶的 40-kDa 片段部分相关。半胱氨酸残基周围的水疗分析表明 2Fe/2S 位点与酶的 20-kDa 片段部分相关。
The primary structure of rat liver xanthine dehydrogenase (EC 1.1.1.204) was determined by sequence analysis of cDNA and purified enzyme. The enzyme consists of 1,319 amino acid residues with a calculated molecular mass of 145,034 Da, including initiation methionine, and is homologous to the previously reported Drosophila melanogaster enzyme (Lee, C. S., Curtis, D., McCarron, M., Love, C., Gray, M., Bender, W., and Chovnick, A. (1987) Genetics 116, 55-66; Keith, T. P., Riley, M. A., Kreitman, M., Lewontin, R. C., Curtis, D., and Chambers, G. (1987) Genetics 116, 67-73) with an identity of 52%. The enzyme exists originally as the NAD-dependent type in a freshly prepared sample. When the purified NAD-dependent type enzyme was digested with trypsin, it cleaved into three fragments with molecular masses of 20, 40, and 85 kDa and was irreversibly converted to the OSdependent type. Comparison of the amino-terminal sequences of the three peptide fragments with the cDNAdeduced sequence reveals that the 20-, 40-, and 85kDa peptide fragments correspond residues to 1-184, 185-539, and 540-1319 of the enzyme, respectively. Comparison of the 5’-p-fluorosulfonylbenzoyladenosine-labeled peptide sequence of the chicken enzyme (Nishino, T., and Nishino, T. (1989) J. Biol. Chem. 264,5468-5473) reveals that the NAD binding site is associated with the 40-kDa fragment portion of the enzyme. Hydropathy analysis around the cysteine residues suggests that the 2Fe/2S sites are associated with the 20-kDa fragment portion of the enzyme.