Glutamine deamidation: an indicator of antiquity, or preservational quality?

Much credence has been given in the paleoproteomic community to glutamine deamidation as a proxy for the age of proteins derived from fossil and subfossil material, and this modification has been invoked as a means for determining the endogeneity of molecules recovered from very old fossil specimens.We re-evaluated the relationship between glutamine deamidation and geologic time by examining previously published data from five recent mass...