One of the methods of protein crosslinking used in the synthesis of protein-based nanoparticles is the formation of bityrosine bridges, which may be achieved by the recombination of phenoxyl-type radicals in irradiated protein solutions. Radiation-induced formation of phenoxyl radicals in tyrosine is promoted in presence of H⁺. In this work, kinetics of this process and the influence of pH were studied by pulse radiolysis measurements of a model peptide H-Gly-Tyr-Gly-OH (GYG), which may help to solve questions raised for bigger, more complex systems in comparable conditions. The main route of phenoxyl radicals formation consists of the addition reaction of hydroxyl radical to the phenol ring on the tyrosine side-chain and proton catalyzed water molecule elimination. A similar effect was observed in studies of tripeptide solutions containing phosphate buffer. The presented data include time-resolved optical spectroscopy of transient species formed under pulse electron beam irradiation and a comparison of the kinetics of the phenoxyl radicals formation in samples at various pH and in presence of phosphate buffer. The postulated mechanism and obtained values of rate constants of the formation and decay of transient species were additionally checked by simple probabilistic simulations.

用于合成基于蛋白质的纳米粒子的蛋白质交联方法之一是联酪氨酸桥的形成，这可以通过在辐照的蛋白质溶液中苯氧基型自由基的重组来实现。在 H ⁺存在下促进辐射诱导的酪氨酸中苯氧基自由基的形成. 在这项工作中，该过程的动力学和 pH 值的影响通过模型肽 H-Gly-Tyr-Gly-OH (GYG) 的脉冲辐解测量进行了研究，这可能有助于解决对更大、更复杂的系统提出的问题。可比条件。苯氧基自由基形成的主要途径包括羟基自由基与酪氨酸侧链上的苯酚环的加成反应和质子催化的水分子消除。在含有磷酸盐缓冲液的三肽溶液的研究中观察到类似的效果。所提供的数据包括脉冲电子束照射下形成的瞬态物质的时间分辨光谱，以及在不同 pH 值和磷酸盐缓冲液存在下的样品中苯氧基自由基形成动力学的比较。