Biochemical assay of proteomic libraries derived from theSaccharomyces cerevisiaegenome provides a powerful new tool for the assignment of activities to proteins. Particular advantages of this approach include the speed with which a protein can be identified and the generality for any biological activity for which an assay can be developed. We discuss the utility of this approach for the identification of RNA-modifying enzymes using a yeast proteomic library derived from a genomic set of strains expressing GST-ORF fusion proteins. This technique is also broadly applicable to other classes of RNA-protein interactions, including RNA binding and RNA degradation, and can be used with any of the proteomic libraries that are available.
