The computational importance of guanosine monophosphate (GMP) comes from its importance in the synthesis of nucleic acids. Deamination reaction mechanisms, kinetics, and thermodynamics of GMP with 3H₂O and 2H₂O/OH⁻ to produce xanthosine monophosphate (XMP) have been investigated. The proposed reactions were optimized in the gas-phase and in an aqueous medium. Two key steps were found for the proposed pathways: a tetrahedral intermediate formation and a single water-mediated six-membered ring transition state, yielding the desired product. The deamination of GMP with 2H₂O/OH⁻ yield deprotonated XMP⁻ with only one pathway, which is highly exothermic, and the activation energy is significantly lower (33 kJ mol^-1 at M11/6-31G(d)) compared to the other pathways. Our results suggest that pathway C is the most kinetically and thermodynamically favorable mechanism for the deamination of GMP with 3H₂O with the lowest energy barrier of 123 kJ mol^-1, due to multiple functions of water that enhance the reaction profile.

鸟苷一磷酸（GMP）的计算重要性来自其在核酸合成中的重要性。脱氨反应的机制，动力学，并用3H GMP的热力学₂ O和2H ₂ O / OH ^-以产生黄苷单磷酸（XMP）进行了研究。拟议的反应在气相和水性介质中进行了优化。对于拟议的途径，发现了两个关键步骤：四面体中间体的形成和单水介导的六元环过渡态，产生了所需的产物。GMP与2H脱氨₂ O / OH ^-屈服去质子XMP ^-与其他途径相比，只有一个途径是高度放热的，活化能明显较低（在M11 / 6-31G（d）处为33 kJ mol ^-1）。我们的结果表明，途径3 C是用3H ₂ O脱氨GMP的动力学和热力学上最有利的机理，其最低能垒为123 kJ mol ^-1，这是由于水的多种功能增强了反应特性。