A paper published this week in PNAS from scientists at the Broad Institute looks at how to better identify the proteins to which small molecules and drugs bind to effect their mechanism of action. The group used a combination of quantitative proteomics, or SILAC, and affinity enrichment to find these proteins in an "unbiased, robust and comprehensive" way. Particularly, they detail applying the method to identifying targets of kinase inhibitors and immunophilin binders.