DNA酶I

脱氧核糖核酸酶 I

D128590-500UN

500U

EnzymoPure™

≥2,000 Kunitz units/ml；来源于牛胰腺；无Ribonuclease & Protease，溶液

Bovine pancreatic deoxyribonuclease is an endonuclease which splits phosphodiester linkages, preferentially adjacent to a pyrimidine nucleotide yielding polynucleotides with free hydroxyl group at the 3' position and phosphate group at the 5' position. The average chain length of a limit digest is a tetranucleotide.用于从蛋白质样品中除去 DNA。 Deoxyribonuclease I from bovine pancreas has been used in a study to compare several procedures for reducing RNase contamination in preparations of DNase. Deoxyribonuclease I from bovine pancreas has also been used in a study to investigate the effect of the composition of sodium dodecyl sulfate preparations on the renaturation of enzymes after polyacrylamide gel electrophoresis. B bpDNase I is not base nor sequence specific; however, it does not cleave randomly. It shows preference for cleavage at the 5’ side of pyrimidines, and is particularly pronounced in alternative copolymers (Bernardi et al. 1975, and Lomonossoff et al. 1981). It has been shown that variations in the twist angle are recognized by DNase I (Dickerson and Drew 1981). The specificity of DNase I also depends on the divalent cations present. In the presence of Ca2+ and Mg2+, it causes single strand breaks, and in the presence of Mn2+ double strand breaks have been reported (Junowicz and Spencer 1973, and Campbell and Jackson 1980). Protein Accession Number: P00639 CATH Classification (v. 3.2.0): Class: Alpha Beta Architecture: 4-Layer Sandwich Topology: Deoxyribonuclease I; Chain A Molecular Weight: 29.1 kDa (Theoretical) Optimal pH: 7.8 Isoelectric Point: 5.08 (Theoretical) Extinction Coefficient: 36,750 cm-1 M-1 E1%,280 = 11.1 Active Site Residues: Tyrosine (Y87) Glutamate (E100) Histidine (H156) Activators: Bivalent metal ions (Junowicz and Spencer 1973b, Poulos and Price 1972, Price 1969, and Price 1975) Inhibitors: 2-mercaptoethanol (Laskowski 1971) 2-nitro-5-thiocyanobenzoic acid (Moore 1981) Actin (Mannherz et al. 2008, and Lazarides and Lindberg 1974) Alfatoxin B2a, G2, G2a, and M1 (non-competitive) (Schabort 1970) EGTA (Moore 1981) and EDTA (Junowicz and Spencer 1973) Sodium dodecyl sulfate (Liao 1975a) Calf spleen inhibitor protein (Laskowski 1971) Carbodiimide and cholesterol sulfate (Iwamori 2000) Iodoacetate (Moore 1981) Applications: DNA removal in primary cell isolation: decreases viscosity providing better yields DNA removal in bioprocessing applications Removing genomic DNA from RNA preparations prior to RT-PCR in vitro transcription Nick translation DNase footprinting Actin binding UV crosslinking of proteins to nucleic acids Radioactive labeling

DNase I 是一种内切酶，可作用于嘧啶附近的磷酸二酯键，生成末端带有 5′-磷酸的多核苷酸。在 Mg2+ 存在的情况下，DNAse I 可独立裂解 DNA 的每一条链，裂解位点是随机的。在 Mn2+ 存在的情况下，两条 DNA 链会在大致相同的部位被裂解。Mn2+、Ca2+、Co2+ 和 Zn2+ 等二价阳离子是该酶的活化剂。浓度为 5 mM 的 Ca2+ 能使酶稳定，防止蛋白水解。最佳 pH 值为 7 至 8。牛胰腺中的 DNAse I 由 A、B、C 和 D 四种色谱法可区分的成分组成，它们的摩尔比分别为 4:1:1。其中只有少量的 D。已知 2-巯基乙醇、螯合剂、十二烷基硫酸钠（SDS）6 和肌动蛋白7 可抑制酶的活性。

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