Analysis of Methods for Extracting Matrix Proteins from Human Kidney Stones

Five techniques for the extraction of proteins from kidney stones were compared for the purpose of maximizing yield for mass spec analysis. The proteomics of kidney stones may provide insight into the underlying mechanisms of stone formation and why some people are more prone to developing kidney stones than others. Kidney stones contain proteins that may serve as markers for a wide variety of disease states. Mass spectrometry offers the ability to identify and quantify the complete proteome of a kidney stone. To date, there have been only a limited number of research projects aimed at studying the protein composition of kidney stones, possibly due to the difficulty in extracting these proteins while preserving the ability to subject the samples to mass spectrometry. We compared five methods for extracting kidney stone matrix proteins, three from previously published studies and two methods we designed based on previous studies. We were able to establish which methods produced the highest yield of protein for both calcium oxalate and uric acid stones.