Attomole quantitation of protein separations with accelerator mass spectrometry

Quantification of specific proteins depends on separation by chromatography or electrophoresis followed by chemical detection schemes such as staining and fluorophore adhesion. Chemical exchange of short-lived isotopes, parti cularly sulfur, is also prevalent despite the inconveniences of counting ra dioactivity. Physical methods based on isotopic and elemental analyses offe r highly sensitive protein quantitation that has linear response over wide dynamic ranges and is independent of protein conformation. Accelerator mass spectrometry quantifies long-lived isotopes such as C-14 to subattomole se nsitivity, We quantified protein interactions with small molecules such as toxins, vitamins, and natural biochemicals at precisions of 1-5%. Micro-pro ton induced X-ray emission quantifies elemental abundances in separated met alloprotein samples to nanogram amounts and is capable of quantifying phops phorylated loci in gels. Accelerator-based quantitation is a possible tool for quantifying the genome translation into proteome.