Isoguanine
(Synonyms: 异鸟嘌呤) 目录号 : GC33662
An isomer of guanine
Cas No.:3373-53-3
Sample solution is provided at 25 µL, 10mM.
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Quality Control & SDS
- View current batch:
- Purity: >97.00%
- COA (Certificate Of Analysis)
- SDS (Safety Data Sheet)
- Datasheet
Isoguanine is a natural isomer of guanine originally isolated from Croton seed but is also a product of oxidative damage to the adenine base in DNA.1,2 It can be formed through oxidative damage to deoxyadenosine and deoxyadenosine-ATP (d-ATP) as well as single- and double-stranded DNA and induces a parallel-stranded DNA structure when incorporated into DNA.2,3 It is mutagenic to S. tymphimurium in the Ames test and induces sister chromatid exchange, a measure of mutagenicity, in isolated human peripheral blood lymphocytes.4
1.Cherbuliez, E., and Bernhard, K.Croton seed. I. Crotonoside (2-hydroxy-6-aminopurine-d-riboside)Helv. Chim. Acta15464-471(1932) 2.Cheng, Q., Gu, J., Compaan, K.R., et al.Isoguanine formation from adenineChemistry18(16)4877-4886(2012) 3.Kamiya, H., and Kasai, H.2-Hydroxyadenine (isoguanine) as oxidative DNA damage: Its formation and mutation inducibilityNucleic Acids Symp. Ser.(34)233-234(1995) 4.Arashidani, K., Iwamoto-Tanaka, N., Muraoka, M., et al.Genotoxicity of ribo- and deoxyribonucleosides of 8-hydroxyguanine, 5-hydroxycytosine, and 2-hydroxyadenine: Induction of SCE in human lymphocytes and mutagenicity in Salmonella typhimurium TA 100Mutat. Res.403(1-2)223-227(1998)
| Cas No. | 3373-53-3 | SDF | |
| 别名 | 异鸟嘌呤 | ||
| Canonical SMILES | NC1=NC(NC2=C1NC=N2)=O | ||
| 分子式 | C5H5N5O | 分子量 | 151.13 |
| 溶解度 | 1 M NaOH: *50 mg/ml | 储存条件 | Store at -20°C |
| General tips | 请根据产品在不同溶剂中的溶解度选择合适的溶剂配制储备液；一旦配成溶液，请分装保存，避免反复冻融造成的产品失效。 储备液的保存方式和期限：-80°C 储存时，请在 6 个月内使用，-20°C 储存时，请在 1 个月内使用。 为了提高溶解度，请将管子加热至37℃，然后在超声波浴中震荡一段时间。 |
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| Shipping Condition | 评估样品解决方案：配备蓝冰进行发货。所有其他可用尺寸：配备RT，或根据请求配备蓝冰。 | ||
| 制备储备液 | |||
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1 mg | 5 mg | 10 mg |
| 1 mM | 6.6168 mL | 33.0841 mL | 66.1682 mL |
| 5 mM | 1.3234 mL | 6.6168 mL | 13.2336 mL |
| 10 mM | 0.6617 mL | 3.3084 mL | 6.6168 mL |
| 第一步：请输入基本实验信息（考虑到实验过程中的损耗，建议多配一只动物的药量） | ||||||||||
| 给药剂量 | mg/kg |  |
动物平均体重 | g | |
每只动物给药体积 | ul | |
动物数量 | 只 |
| 第二步：请输入动物体内配方组成（配方适用于不溶于水的药物；不同批次药物配方比例不同，请联系GLPBIO为您提供正确的澄清溶液配方） | ||||||||||
| % DMSO % % Tween 80 % saline | ||||||||||
| 计算重置 | ||||||||||
计算结果:
工作液浓度： mg/ml；
DMSO母液配制方法： mg 药物溶于 μL DMSO溶液（母液浓度 mg/mL，
体内配方配制方法：取 μL DMSO母液，加入 μL PEG300，混匀澄清后加入μL Tween 80，混匀澄清后加入 μL saline，混匀澄清。
1. 首先保证母液是澄清的；
2.
一定要按照顺序依次将溶剂加入，进行下一步操作之前必须保证上一步操作得到的是澄清的溶液，可采用涡旋、超声或水浴加热等物理方法助溶。
3. 以上所有助溶剂都可在 GlpBio 网站选购。
Photodynamics of alternative DNA base Isoguanine
Phys Chem Chem Phys 2019 Jun 26;21(25):13474-13485.PMID:31204732DOI:10.1039/c9cp01622h.
Isoguanine is an alternative nucleobase that has been proposed as a component of expanded genetic codes. It has also been considered as a molecule with potential relevance to primordial informational polymers. Here, we scrutinize the photodynamics of Isoguanine, because photostability has been proposed as a critical criterion for the prebiotic selection of biomolecular building blocks on an early Earth. We discuss resonance-enhanced multiphoton ionization, IR-UV double resonance spectroscopy and pump-probe measurements performed for this molecule to track the excited-state behaviour of its different tautomeric forms in the gas phase. These experiments, when confronted with highly accurate quantum chemical calculations and nonadiabatic dynamics simulations provide a complete mechanistic picture of the tautomer-specific photodynamics of Isoguanine. Our results indicate that UV-excited enol tautomers of Isoguanine are relatively short lived and therefore photostable. In contrast, the biologically more relevant keto forms are trapped in dark nπ* states which are sufficiently long lived to participate in destructive photochemistry. The resulting lower photostability compared to canonical nucleobases may have been one of the reasons why Isoguanine was not incorporated into DNA and RNA.
Isoguanine formation from adenine
Chemistry 2012 Apr 16;18(16):4877-86.PMID:22411110DOI:10.1002/chem.201102415.
Several possible mechanisms underlying Isoguanine formation when OH radical attacks the C(2) position of adenine (A C 2) are investigated theoretically for the first time. Two steps are involved in this process. In the first step, one of two low-lying A C 2⋅⋅⋅OH reactant complexes is formed, leading to C(2)-H(2) bond cleavage. Between the two reactant complexes there is a small isomerization barrier, which lies well below separated adenine plus OH radical. The complex dissociates to free molecular hydrogen and an Isoguanine tautomer (isoG 1 or isoG 2). The local and activation barriers for the two pathways are very similar. This evidence suggests that the two pathways are competitive. After dehydrogenation, there are two possible routes for the second step of the reaction. One is direct hydrogen transfer, via enol-keto tautomerization, which has high local barriers for both tautomers and is not favored. The other option is indirect hydrogen transfer involving microsolvation by one water molecule. The water lowers the reaction barrier by over 20 kcal mol(-1) , indicating that water-mediated hydrogen transfer is much more favorable. Both A+OH(⋅) →isoG+H(⋅) reactions are exothermic and spontaneous. Among four Isoguanine tautomers, isoG 1 has the lowest energy. Our findings explain why only the N(1)H and O(2)H tautomers of isolated Isoguanine and isoguanosine have been observed experimentally.
Mechanism of the deamination reaction of Isoguanine: a theoretical investigation
J Phys Chem A 2013 Jul 18;117(28):5715-25.PMID:23789717DOI:10.1021/jp4031738.
Mechanisms of the deamination reactions of Isoguanine with H2O, OH(-), and OH(-)/H2O and of protonated Isoguanine (isoGH(+)) with H2O have been investigated by theoretical calculations. Eight pathways, paths A-H, have been explored and the thermodynamic properties (ΔE, ΔH, and ΔG), activation energies, enthalpies, and Gibbs energies of activation were calculated for each reaction investigated. Compared with the deamination reaction of Isoguanine or protonated Isoguanine (isoGH(+)) with water, the deamination reaction of Isoguanine with OH(-) shows a lower Gibbs energy of activation at the rate-determining step, indicating that the deamination reaction of Isoguanine is favorably to take place for the deprotonated form isoG(-) with water. With the assistance of an extra water, the reaction of Isoguanine with OH(-)/H2O, pathways F and H, are found to be the most feasible pathways in aqueous solution due to their lowest Gibbs energy of activation of 174.7 and 172.6 kJ mol(-1), respectively, at the B3LYP/6-311++G(d,p) level of theory.
Rescue of the orphan enzyme Isoguanine deaminase
Biochemistry 2011 Jun 28;50(25):5555-7.PMID:21604715DOI:10.1021/bi200680y.
Cytosine deaminase (CDA) from Escherichia coli was shown to catalyze the deamination of Isoguanine (2-oxoadenine) to xanthine. Isoguanine is an oxidation product of adenine in DNA that is mutagenic to the cell. The Isoguanine deaminase activity in E. coli was partially purified by ammonium sulfate fractionation, gel filtration, and anion exchange chromatography. The active protein was identified by peptide mass fingerprint analysis as cytosine deaminase. The kinetic constants for the deamination of Isoguanine at pH 7.7 are as follows: k(cat) = 49 s(-1), K(m) = 72 μM, and k(cat)/K(m) = 6.7 × 10(5) M(-1) s(-1). The kinetic constants for the deamination of cytosine are as follows: k(cat) = 45 s(-1), K(m) = 302 μM, and k(cat)/K(m) = 1.5 × 10(5) M(-1) s(-1). Under these reaction conditions, Isoguanine is the better substrate for cytosine deaminase. The three-dimensional structure of CDA was determined with Isoguanine in the active site.
Photophysical Characterization of Isoguanine in a Prebiotic-Like Environment
Chemistry 2023 Jan 24;e202203580.PMID:36693799DOI:10.1002/chem.202203580.
It is intriguing how a mixture of organic molecules survived the prebiotic UV fluxes and evolved into the actual genetic building blocks. Scientists are trying to shed light on this issue by synthesizing nucleic acid monomers and their analogues under prebiotic Era-like conditions and by exploring their excited state dynamics. To further add to this important body of knowledge, this study discloses new insights into the photophysical properties of protonated Isoguanine, an isomorph of guanine, using steady-state and femtosecond broadband transient absorption spectroscopies, and quantum mechanical calculations. Protonated Isoguanine decays in ultrafast time scales following 292 nm excitation, consistently with the barrierless paths connecting the bright S1 (ππ*) state with different internal conversion funnels. Complementary calculations for neutral Isoguanine predict similar photophysical properties. These results demonstrate that protonated Isoguanine can be considered photostable in contrast to protonated guanine, which exhibits 40-fold longer excited state lifetimes.