HUMAN-URINE DNASE-I - IMMUNOLOGICAL IDENTITY WITH HUMAN PANCREATIC DNASE-I, AND ENZYMIC AND PROTEOCHEMICAL PROPERTIES OF THE ENZYME
HUMAN-URINE DNASE-I - IMMUNOLOGICAL IDENTITY WITH HUMAN PANCREATIC DNASE-I, AND ENZYMIC AND PROTEOCHEMICAL PROPERTIES OF THE ENZYME
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DOI：
10.1093/oxfordjournals.jbchem.a134747
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发表时间：
1984-01-01
影响因子：
2.7
通讯作者：
YAMAMOTO, T
中科院分区：
文献类型：
--
作者：
ITO, K;MINAMIURA, N;YAMAMOTO, T
人尿中的DNA酶I经DEAE-木质纤维素、羟基磷灰石、DEAE-纤维素、SephadexG-75和弹性蛋白-硅藻土柱层析纯化至凝胶均相状态。纯化的酶与人胰腺DNA酶I免疫学上相同，但与牛胰腺DNA酶I不同。该酶的分子量和等电点估计为4.1 × 104。分别为104和3.6。氨基酸分析表明，1摩尔酶含有8摩尔半胱氨酸。通过丹磺酰氯法鉴定N-末端氨基酸为亮氨酸。该酶在Mg ~（2+）、Co ~（2+）和Mn ~（2+）存在下均具有活性。最适pH为6.5左右。该酶在5.0-9.0的pH范围和低于45 ℃的温度下是稳定的。C.天然DNA的酶的水解速度是观察到的热变性DNA的两倍。这种酶彻底降解天然DNA中约20%的磷酸二酯键。该酶也能降解poly（dA）和poly（dT），但几乎不降解poly（dG）和poly（dC）。
DNase I in human urine was purified to an electrophoretically homogeneous state by column chromatographies on DEAE-lignocellulose, hydroxyapatite, DEAE-cellulose, Sephadex G-75 and elastin-celite. The purified enzyme was immunologically identical with human pancreatic DNase I, but not with bovine pancreatic DNase I. The MW and isoelectric point of the enzyme were estimated to be 4.1 .times. 104 and 3.6, respectively. The amino acid analysis revealed that 1 mol of the enzyme contained 8 mol of half-cystine. The N-terminal amino acid was identified as leucine by the dansyl chloride method. The enzyme was active in the presence of Mg2+, Co2+ or Mn2+. The optimum pH was around 6.5. The enzyme was stable in the pH range from 5.0-9.0 and at temperatures lower than 45.degree. C. The rate of hydrolysis of native DNA by the enzyme was twice as fast as that observed with heat-denatured DNA. This enzyme exhaustively degraded about 20% of the phosphodiester bonds in native DNA. The enzyme also degraded poly(dA) and poly(dT), but hardly degraded poly(dG) and poly(dC).