HILAQ: A Novel Strategy for Newly Synthesized Protein Quantification

Ma, Y.; McClatchy, D.B.; Barkallah, S.; et al.

The noncanonical amino acid azidohomoalanine (AHA) has proven effective at measuring the synthesis and turnover of newly synthesized proteins (NSPs) in various biological samples, such as mouse tissue. Described here by Yates et al. is a new metabolic labeling method – termed HILAQ (heavy isotope labeled azidohomoalanine quantification) – for enriching and quantifying NSPs in HEK293T and HT22 cell lines. Experimentally, cells are pulse labeled with light or heavy AHA then mixed (1:1 w/w) and processed by bottom-up LC-MS. Using peptide AHA enrichment as opposed to protein AHA enrichment (as in the QuaNCAT protocol) was found to yield enhanced NSP quantification for improved monitoring of protein dynamics.