6533b7d1fe1ef96bd125cd92

RESEARCH PRODUCT

Thermal stability of nacre proteins of the polynesian pearl oyster: a proteomic study.

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Mollusc shells are organic-inorganic composites that are often preserved in the fossil record. However, the way the organic fraction, also called shell matrix, gets fossilized remains an unsolved question, in spite of several old and more recent studies. In the present paper, we have tried to mimic a diagenetic process by constantly heating for ten days at 100°C fresh nacre powder samples of the Polynesian pearl oyster Pinctadamargaritifera. Each day, aliquots of nacre powder were sampled and the matrix was subsequently extracted. It was further analysed by direct weigh quantification, by immunological techniques and by proteomics. Our preliminary data suggest that nacre proteins, when heated at 100°C in dry condition, degrade rather slowly. We evidenced a differential degradation pattern of the soluble and insoluble fractions, and showed that some nacre proteins of the insoluble fraction are stable after ten days of heating. Factors that influence the diagenetic stability of some shell proteins are discussed.