title: Intra-crystalline protein diagenesis (IcPD) inPatella vulgata. Part II: Breakdown and temperature sensitivity.
abstract: Artificial diagenesis of the intra-crystalline proteins isolated fromPatella vulgatawas 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-fossilPatellaspecimens 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.
authors: BioArCh, Departments of Biology, Archaeology and Chemistry, University of York, York YO10 5DD, UK.
authors: B
authors: B
authors: Demarchi
authors: M J
authors: MJ
authors: Collins
authors: P J
authors: PJ
authors: Tomiak
authors: B J
authors: BJ
authors: Davies
authors: K E H
authors: KE
authors: Penkman
keywords: High-temperature experiments; Intra-crystalline proteins; Kinetic parameters; Patella vulgata; Temperature sensitivity
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