Rajnák Cyril, Imrich Richard, Štofko Juraj, Matonok Andrej, Boča Roman
Faculty of Natural Sciences, University of Ss. Cyril and Methodius, Trnava 917 01, Slovakia.
Faculty of Health Science, University of Ss. Cyril and Methodius, Trnava 917 01, Slovakia.
ACS Omega. 2024 Aug 18;9(34):36086-36098. doi: 10.1021/acsomega.3c10227. eCollection 2024 Aug 27.
Three neurotransmitters belonging to catecholamines (dopamine, noradrenaline, adrenaline) and related α-amino acids (DOPA and tyrosine) were studied by quantum-chemical and DFT calculations using B3LYP and DLPNO-CCSD(T) methods in water. In addition to the three canonical forms, zwitterionic forms were also investigated, each in three oxidation states (molecular cation L, electroneutral molecule L, and molecular anion L). Each species was subjected to geometry optimization followed by vibrational analysis. Electronic properties (adiabatic ionization energy, electron affinity, chemical hardness, molecular electronegativity, electrophilicity index, dipole moment, electric polarizability, and quadrupole moment) and standard thermodynamic quantities (inner energy, entropy, enthalpy, and Gibbs energy) were evaluated, which allows the absolute oxidation and reduction potentials to be calculated. The absolute reduction potential (ARP) was found to correlate with the electrophilicity index ω along a straight line. Moreover, in addition to the standard expression for the absolute redox potential using reaction Gibbs energy, an approximation based on ionization energy and/or electron affinity was also tested. The main finding is that dopamine is a much weaker oxidizing agent with the ARP = 0.99 V relative to tyrosine with ARP = 1.38 V for canonical structures in water. This is also true for the zwitterionic structures in water: for dopamine ARP = 0.63 V is much lower relative to tyrosine with ARP = 1.31 V. The protonated form (DOPAH) has the highest ARP = 2.02 V. Prediction of the redox potentials is an important factor influencing antioxidant (EC) and/or antireductant activity. Based on 16 molecular properties for 20 molecules (320 entries), advanced statistical methods (cluster analysis, principal component analysis, pair-correlation) reveal that several groups of similarity exist: {dopamine-noradrenaline}, different from {adrenaline-DOPA-(tyrosine)} and zwitterionic forms of {dopamine-noradrenaline-adrenaline}.
利用B3LYP和DLPNO-CCSD(T)方法，在水中通过量子化学和密度泛函理论（DFT）计算研究了三种属于儿茶酚胺类的神经递质（多巴胺、去甲肾上腺素、肾上腺素）以及相关的α-氨基酸（多巴和酪氨酸）。除了三种标准形式外，还研究了两性离子形式，每种形式具有三种氧化态（分子阳离子L、电中性分子L和分子阴离子L）。对每种物种进行几何优化，然后进行振动分析。评估了电子性质（绝热电离能、电子亲和能、化学硬度、分子电负性、亲电性指数、偶极矩、电极化率和四极矩）和标准热力学量（内能、熵、焓和吉布斯自由能），这使得能够计算绝对氧化和还原电位。发现绝对还原电位（ARP）与亲电性指数ω呈直线相关。此外，除了使用反应吉布斯自由能的绝对氧化还原电位的标准表达式外，还测试了基于电离能和/或电子亲和能的近似表达式。主要发现是，对于水中的标准结构，多巴胺作为氧化剂的能力要弱得多，其ARP = 0.99 V，而酪氨酸的ARP = 1.38 V。对于水中的两性离子结构也是如此：多巴胺的ARP = 0.63 V相对于酪氨酸的ARP = 1.31 V要低得多。质子化形式（DOPAH）的ARP最高，为2.02 V。氧化还原电位的预测是影响抗氧化（EC）和/或抗还原活性的一个重要因素。基于20个分子的16种分子性质（320个条目），先进的统计方法（聚类分析、主成分分析、成对相关性分析）揭示了存在几组相似性：{多巴胺 - 去甲肾上腺素}，不同于{肾上腺素 - 多巴 -（酪氨酸）}以及{多巴胺 - 去甲肾上腺素 - 肾上腺素}的两性离子形式。
