1. Protein quantification of ancient samples
Protein quantification is an often overlooked but important step in palaeoproteomics due to the unique nature of each sample. An accurate protein quantification allows optimisation of sampling, downstream digestion and clean-up protocols to. Many protein quantification assays are available but the suitability of these to historic and ancient bone and enamel has not been systematically investigated.
Accurate protein quantification of ancient samples is confounded by protein to protein variability, contaminants and diagenesis. For example measuring UV absorbance at 280 nm is a common protein quantification technique that effectively measures the presence of tryptophan (W) and tyrosine (Y) residues. As such the protein concentration of a sample-extraction that contains mostly proteins with few W’s and Y’s (collagen - the most abundant protein in bone) will be underestimated.
Aim: determine protein the single or combination of assay which most accurately quantify protein extracted from historic and ancient samples including bone and enamel.
Additional investigation: can the suitability of a sample to 1 assay but not another provide clues as to the nature of the proteins and or contaminants present? e.g. the collagen to non-collagenous protein ratio.
- Use of colorimetric protein quantification assays
- Microvolume Spectrophotometry
- Protein extraction