(3,4-Dimethoxyphenyl)methanol radical

• 分子结构分类: 有机化合物 - 苯类化合物 - 苯和取代衍生物
• 英文名称: (3,4-Dimethoxyphenyl)methanol radical
• 化学式: C9H11O3
• 分子量: 167.18
• InChiKey: QXYPKMKZEZSVGV-UHFFFAOYSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  0.6
• 重原子数：
  12
• 可旋转键数：
  3
• 环数：
  1.0
• sp3杂化的碳原子比例：
  0.33
• 拓扑面积：
  19.5
• 氢给体数：
  0
• 氢受体数：
  2

反应信息

• 作为产物：
  描述：

  3,4-二甲氧基苄醇 、 双氧水 生成 (3,4-Dimethoxyphenyl)methanol radical 、 水
  参考文献：
  名称：

  木质素过氧化物酶将藜芦醇氧化。

  摘要：

  白腐真菌Phanerochaete chrysosporium的木质素过氧化物酶（LiP）催化真菌的次生代谢产物藜芦醇（VA）的H2O2依赖性氧化为藜芦醛（VAD）。VA的氧化似乎不仅仅是通过LiP化合物I（LiPI）对其阳离子自由基（VA。+）进行单电子氧化，然后通过LiP化合物II（LiPII）进行VAD氧化。此外，通过VA（3 x 10（5）M-1 s-1）进行LiPI还原的速率常数当然足够，但是通过VA（5.0 +/- 0.2 s-1）进行LiPII还原的速率常数不足以达到解释了pH 4.5时LiP的周转率（8 +/- 0.4 s-1）。草酸被发现可以将LiP的转换速率降低到5 s-1，但是它对H2O2或LiPI和LiPII的LiP速率常数没有影响，后者是通过用亚铁氰化物和VA还原LiPI形成的。然而，当通过用VA还原LiPI形成LiPII时，在用VA还原过程中观察到草酸盐敏感的猝

  DOI：

  10.1021/bi00051a037

文献信息

• Detection and Characterization of the Lignin Peroxidase Compound II−Veratryl Alcohol Cation Radical Complex
  作者：Aditya Khindaria、Guojun Nie、Steven D. Aust

  DOI：10.1021/bi9715730

  日期：1997.11.1

  oxidize veratryl alcohol (VA) by two electrons to veratryl aldehyde, although the VA cation radical (VA.+) is an intermediate [Khindaria, A., et al. (1995) Biochemistry 34, 6020-6025]. It was speculated, on the basis of kinetic evidence, that VA*+ can form a catalytic complex with LiP compound II. We have used low-temperature EPR to provide direct evidence for the formation of the complex. The EPR spectrum

  尽管VA阳离子自由基（VA。+）是中间体[Khindaria，A.，et al。（2006）。（1995）Biochemistry 34，6020-6025]。根据动力学证据推测，VA * +可以与LiP化合物II形成催化络合物。我们已使用低温EPR为复合物的形成提供直接证据。VA * +在4 K时获得的EPR谱由血红素（S = 1）的oxoferryl部分与VA。+（S = 1/2）之间耦合的模型解释，类似于为oxyferryl和oxferryl提出的模型。辣根过氧化物酶的卟啉正阳离子。偶合常数表明VA。+被铁氧和反铁磁地偶合到氧杂芳基部分上。用g垂直仅略大于g平行的g来模拟光谱。这是令人惊讶的，因为在过氧化物酶中与血红素铁偶合的唯一其他已知的有机基团是细胞色素c过氧化物酶中的色氨酸阳离子基团，该基团显示出g张量，其中g平行于g垂直于g垂直。自旋浓度分析表明每摩尔酶将1摩尔VA * +偶联至草酰氧部分。VA。+信号以1
• Characterization of the oxycomplex of lignin peroxidases from Phanerochaete chrysosporium: equilibrium and kinetics studies
  作者：Danying Cai、Ming Tien

  DOI：10.1021/bi00460a018

  日期：1990.2.27

  The oxycomplexes (compound III, oxyperoxidase) of two lignin peroxidase isozymes, H1 (pI = 4.7) and H8 (pI = 3.5), were characterized in the present study. After generation of the ferroperoxidase by photochemical reduction with deazoflavin in the presence of EDTA, the oxycomplex is formed by mixing ferroperoxidase with O2. The oxycomplex of isozyme H8 is very stable, with an autoxidation rate at 25 degrees C too slow to measure at pH 3.5 or 7.0. In contrast, the oxycomplex of isozyme H1 has a half-life of 52 min at pH 4.5 and 29 min at pH 7.5 at 25 degrees C. The decay of isozyme H1 oxycomplex follows a single exponential. The half-lives of lignin peroxidase oxycomplexes are much longer than those observed with other peroxidases. The binding of O2 to ferroperoxidase to form the oxycomplex was studied by stopped-flow methods. At 20 degrees C, the second-order rate constants for O2 binding are 2.3 X 10(5) and 8.9 X 10(5) M-1 s-1 for isozyme H1 and 6.2 X 10(4) and 3.5 X 10(5) M-1 s-1 for isozyme H8 at pH 3.6 and pH 6.8, respectively. The dissociation rate constants for the oxycomplex of isozyme H1 (3.8 Z 10(-3) s-1) and isozyme H8 (1.0 X 10(-3) s-1) were measured at pH 3.6 by CO trapping. Thus, the equilibrium constants (K, calculated from kon/koff) for both isozymes H1 (7.0 X 10(7) M-1) and H8 (6.2 X 10(7) M-1) are higher than that of myoglobin (1.9 Z 10(6) M-1).(ABSTRACT TRUNCATED AT 250 WORDS)
• Two Substrate Interaction Sites in Lignin Peroxidase Revealed by Site-Directed Mutagenesis
  作者：Wendy A. Doyle、Wolfgang Blodig、Nigel C. Veitch、Klaus Piontek、Andrew T. Smith

  DOI：10.1021/bi981633h

  日期：1998.10.1

  It has been shown recently that Trp171 of lignin peroxidase (LiP) is hydroxylated at the CP position [Blodig, W., Doyle, W. A., Smith, A. T., Winterhalter, K., Choinowski, T., and Piontek, K. (1998) Biochemistry 37, 8832-8838]. Comparative experiments, carried out on both wild-type fungal and recombinant LIP isoenzyme H8 (LiPH8*), indicate that the process of hydroxylation is autocatalytic and that Trp171 may be implicated in catalysis. The role of this residue has therefore been examined using site-directed mutagenesis to obtain recombinant enzymes with Trp171 substituted by Phe or Ser (W171F and W171S LiPH8*, respectively). The wild-type recombinant enzyme (LiPH8*) was analyzed in solution using H-1 NMR spectroscopy and its integrity confirmed prior to the kinetic and spectroscopic characterization of LiPH8* mutants. A charge neutralization mutation in the "classical heme edge" substrate access channel of LiP, in which Glu146 was substituted by Gly (E146G LiPH8*), showed substantial activity with respect to veratryl alcohol (VA) oxidation and a marked (2.4 pH units) increase in pK(a) for the oxidation of a negatively charged difluoroazo dye. More surprisingly, the Trp171 LiPH8* mutants W171F and W171S LiPH8* were found to have lost all activity with VA as substrate, and compounds I and II were unable to react with VA. Both mutants, however, retained substantial activity with two dye substrates. These data provide the first direct evidence for the existence of two distinct substrate interaction sites in LiP, a heme-edge site typical of those encountered in other peroxidases and a second, novel site centered around Trp171 which is required for the oxidation of VA. Stopped-flow kinetic studies showed that all the mutants examined reacted normally with hydrogen peroxide to give a porphyrin cation radical (compound I). However, the rapid phase of spontaneous compound I reduction (2.3 s(-1)), typical of wildtype LiP, was absent in the Trp171 mutants, strongly suggesting that an electron-transfer pathway must exist within the protein leading from the heme to a surface site in close proximity to Trp171. The kinetic competence of such a pathway is dependent on interaction of the enzyme with VA, at or near Trp171.
• Wariishi H.; Marquez L.; Dunford H.B., J Biol Chem, 1990, 0021-9258, 11137-42
  作者：Wariishi H.、Marquez L.、Dunford H.B.、Gold M.H.

  DOI：——

  日期：——
• Stabilization of the Veratryl Alcohol Cation Radical by Lignin Peroxidase
  作者：Aditya Khindaria、Isao Yamazaki、Steven D. Aust

  DOI：10.1021/bi9601666

  日期：1996.1.1

  Lignin peroxidase (LiP) catalyzes the H2O2-dependent oxidation of veratryl alcohol (VA) to veratryl aldehyde, with the enzyme-bound veratryl alcohol cation radical (VA(.+)) as an intermediate [Khindaria et al. (1995) Biochemistry 34, 16860-16869]. The decay constant we observed for the enzyme-generated cation radical did not agree with the decay constant in the literature [Candeias and Harvey (1995) J. Biol. Chem. 270, 16745-16748] for the chemically generated radical. Moreover, we have found that the chemically generated VA(.+) formed by oxidation of VA by Ce(IV) decayed rapidly with a first-order mechanism in air- or oxygen-saturated solutions, with a decay constant of 1.2 x 10(3) s(-1), and with a second-order mechanism in argon-saturated solution. The first-order decay constant was pH-independent suggesting that the rate-limiting step in the decay was deprotonation. When VA(.+) was generated by oxidation with LiP the decay also occurred with a first-order mechanism but was much slower, 1.85 s(-1), and was the same in both oxygen- and argon-saturated reaction mixtures, However, when the enzymatic reaction mixture was acid-quenched the decay constant of VA(.+) was close to the one obtained in the Ce(IV) oxidation system, 9.7 x 10(2) s(-1). This strongly suggested that the LiP-bound VA(.+) was stabilized and decayed more slowly than free VA(.+). We propose that the stabilization of VA(.+) may be due to the acidic microenvironment in the enzyme active site, which prevents deprotonation of the radical and subsequent reaction with oxygen. We have also obtained reversible redox potential of VA(.+)/VA couple using cyclic voltammetery. Due to the instability of VA(.+) in aqueous solution the reversible redox potential was measured in acetone, and was 1.36 V vs normal hydrogen electrode. Our data allow us to propose that enzymatically generated VA(.+) can act as a redox mediator but not as a diffusible oxidant for LiP-catalyzed lignin or pollutant degradation.