Long-term stability of human proteome

The abundances of 31 major proteins in human plasma, measured by selected reaction monitoring (SRM) mass spectrometry, remained remarkably steady over 4 months, strengthening their case to be used as disease biomarkers, say researchers in Australia. In the first reported use of SRM to measure the changes in the circulating levels of proteins, blood from 10 volunteers was depleted of human serum albumin and immunoglobulin G, which tend to mask other proteins due to their own high blood content, then 39 tryptic peptide fragments of 31 high-to-medium abundance proteins were monitored regularly. The findings are discussed in Proteomics – Clinical Applications.

Within each particular individual, the variations in the protein levels were consistently low. However, when the levels of the individuals were compared with each other, the variations were notably greater. This confirms that people have an individual proteome which is stable, suggesting that any variations introduced by a disease or its treatment can be monitored by following particular proteins as biomarkers.

This kind of approach is another step towards personalised medicine, although the results need to be validated in a broader study and the effects of diurnal cycles need to be incorporated.