Microarray technologies in the field of genomics (transcriptomics), and mass spectrometry and bioinformatics technologies in proteomics, have facilitated the specific and global analyses of genes and their expression, and this has accelerated understanding the molecular basis of disease. These technologies, coupled with two-dimensional gel electrophoresis, mass spectrometry enhanced with chromatographic separations such as MudPIT (Shaw et al., 2008) , or isotope coding-ICAT (Yan et al., 2004) , iTRAQ (Lu et al., 2012) , and SILAC (Coombs et al., 2010) , have provided valuable insight into the quantitative differences in protein abundance during virus infections. However, these methods lack the inherent ability to profile and distinguish proteins according to their actual biological activities or functional state, which has more important bearings on understanding the implications of these macromolecules in vivo (Barglow and Cravatt, 2007) . The lack of functional assessment of these other omic methods has prompted the development of alternative strategies such as ABPP, for the discovery and characterization of enzyme activities within highly complex biological samples.