DNAase

DNAase (Deoxyribonuclease I, DNase I) (EC 3.1.21.1) is an endonuclease that can cleave single-stranded and double-stranded DNA, hydrolyzing phosphodiester bonds to form two products with 5'-phosphate termini and 3'-OH termini ^[1]. DNase I is often used to enzymatically separate residual DNA in the digestion system of cells, or to study DNA-protein interactions using DNase I footprinting ^{[2, 3]}. DNase I digestion of cells can increase cell viscosity without destroying cell integrity ^[4]. The activity of DNase I is strictly dependent on Ca²⁺ and is activated by Mg²⁺ or Mn²⁺ ions ^[5]. During the large-scale production of mRNA, the transcription template needs to be removed after transcription is completed. DNase I can randomly decompose single-stranded or double-stranded DNA to the same extent to generate oligonucleotides with 5'-P ends. Under Mg²⁺ conditions, DNase I can randomly shear double-stranded DNA^{[6, 7]}. This product is derived from bovine pancreas, the specific activity is ≥2000 Kunit Units/mg protein, stable at pH 7-8, and has a molecular weight of approximately 31 kDa.

Activity definition: DNase I catalyzes substrate DNA at 25°C and pH 5.0, resulting in a change of 0.001 in ∆A260 per milliliter per minute, which is defined as one Kunitz unit.

In vivo, DNase I (1000 U/500 μL) was injected intravenously into mice undergoing tenotomy, disrupting the DNA scaffold of neutrophil extracellular traps (NETs) and increasing neutrophil infiltration after injury^[8].

References:
[1]Lauková L, Konečná B, Janovičová Ľ, et al. Deoxyribonucleases and their applications in biomedicine[J]. Biomolecules, 2020, 10(7): 1036.
[2]Miersch C, Stange K, Röntgen M. Effects of trypsinization and of a combined trypsin, collagenase, and DNase digestion on liberation and in vitro function of satellite cells isolated from juvenile porcine muscles[J]. In Vitro Cellular & Developmental Biology-Animal, 2018, 54: 406-412.
[3]Antunes A, Golfieri G, Ferlicca F, et al. HexR controls glucose-responsive genes and central carbon metabolism in Neisseria meningitidis[J]. Journal of Bacteriology, 2016, 198(4): 644-654.
[4]Sapio R T, Burns C J, Pestov D G. Effects of hydrogen peroxide stress on the nucleolar redox environment and pre-rRNA maturation[J]. Frontiers in Molecular Biosciences, 2021, 8: 678488.
[5]Fraser M J, Tynan S J, Papaioannou A, et al. Endo-exonuclease of human leukaemic cells: evidence for a role in apoptosis[J]. Journal of Cell Science, 1996, 109(9): 2343-2360.
[6]Suck D. DNA recognition by DNase I[J]. Journal of Molecular Recognition, 1994, 7(2): 65-70.
[7]Sam M. Mechanistic studies on chemical and biological nucleases[M]. University of California, Los Angeles, 2005.
[8]Agarwal S, Loder S J, Cholok D, et al. Disruption of neutrophil extracellular traps (NETs) links mechanical strain to post-traumatic inflammation[J]. Frontiers in immunology, 2019, 10: 2148.

DNAase（Deoxyribonuclease I，DNase I）（EC 3.1.21.1）脱氧核糖核酸酶是一种可酶切单链和双链DNA的核酸内切酶，能够水解磷酸二酯键，形成具有5'-磷酸末端和3'-OH末端的两种产物^[1]。DNase I常用于酶法分离细胞中消化体系内残余的DNA，或者用于DNase I足迹法进行DNA-蛋白相互作用研究^{[2, 3]}。

DNase I消化细胞可以增加细胞粘度，不会破坏细胞完整性^[4]。DNase I的活性严格依赖于Ca²⁺，由Mg²⁺或Mn²⁺离子活化^[5]。在mRNA大规模生产过程中，转录结束后需要对转录模板进行去除，DNase I可以将单链或者双链DNA进行同等程度的随机分解，生成具有5'-P末端寡核苷酸，在Mg²⁺条件下，DNase I可以对双链DNA进行随意剪切^{[6, 7]}。本产品来自牛胰腺，色谱纯化制备，比活≥2000Kunit Units/mg蛋白，pH7-8时稳定，分子量约为31kDa。

活力定义：25℃，pH5.0条件下DNase I催化底物DNA，使每毫升每分钟∆A260增力加0.001的变化定义为一个酶活力单位（Kunitz unit）。

在体内，DNase I（1000 U/500 μL）通过静脉注射治疗接受腱切断术的小鼠，破坏了中性粒细胞胞外陷阱（NET）的DNA支架，增加了损伤后中性粒细胞浸润^[8]。