Artificial diagenesis of the intra-crystalline proteins isolated from Patella vulgata was induced by isothermal heating at 140 °C, 110 °C and 80 °C. Protein breakdown was quantified for multiple amino acids, measuring the extent of peptide bond hydrolysis, amino acid racemisation and decomposition. The patterns of diagenesis are complex; therefore the kinetic parameters of the main reactions were estimated by two different methods: 1) a well-established approach based on fitting mathematical expressions to the experimental data, e.g. first-order rate equations for hydrolysis and power-transformed first-order rate equations for racemisation; and 2) an alternative model-free approach, which was developed by estimating a “scaling” factor for the independent variable (time) which produces the best alignment of the experimental data. This method allows the calculation of the relative reaction rates for the different temperatures of isothermal heating.

High-temperature data were compared with the extent of degradation detected in sub-fossil Patella specimens of known age, and we evaluated the ability of kinetic experiments to mimic diagenesis at burial temperature. The results highlighted a difference between patterns of degradation at low and high temperature and therefore we recommend caution for the extrapolation of protein breakdown rates to low burial temperatures for geochronological purposes when relying solely on kinetic data.

从普通髌骨中分离出的晶体内蛋白质的人工成岩作用由 140 °C、110 °C 和 80 °C 等温加热诱导。对多种氨基酸的蛋白质分解进行量化，测量肽键水解、氨基酸外消旋化和分解的程度。成岩作用的模式很复杂；因此，主要反应的动力学参数通过两种不同的方法进行估计：1) 基于对实验数据拟合数学表达式的成熟方法，例如水解的一级速率方程和功率转换的一级速率方程外消旋化；2）另一种无模型方法，它是通过估计自变量（时间）的“缩放”因子而开发的，该因子产生实验数据的最佳对齐。

将高温数据与已知年龄的亚化石髌骨标本中检测到的降解程度进行了比较，我们评估了动力学实验在埋藏温度下模拟成岩作用的能力。结果强调了低温和高温下降解模式之间的差异，因此我们建议在仅依赖动力学数据时，出于地质年代学目的将蛋白质分解率外推到低埋藏温度时要谨慎。