Because IPL allows the fusion of synthetic peptides, as well as bacterially expressed proteins, to a protein expressed in the IMPACT system, IPL has been used in a variety of ways including: The expression of cytotoxic proteins [Evans et al., (1998) Protein Sci.7: 2256-2264]. The labeling of proteins with radioactive compounds as well as with synthetic peptides containing biotin or fluorescein [Chong et al., (1997) Gene 192: 277-281; Evans et al., (1998) Protein Sci.7: 2256-2264, Muir et al.,(1998) Proc. Natl. Acad. Sci. USA 95:6705-6710] The study of protein-protein interactions [Severinov et al., (1998) J. Biol. Chem. 273:16205-16209] The generation of kinase substrates by varying the kinase recognition site at the protein level instead of at the DNA level [Ghosh, I. et al., (2004 J. of Imm. Methods. 293:85-95; Xu, J. et al., (2004) Biotechniques. 36: 976 -981.] The generation of phosphatase substrates [Kochinyan, S. et. al. (2007) Use of intein-mediated phosphoprotein arrays to study substrate specificity of protein phosphatases. Biotechniques 42(1): 63-9] The isotopic labeling of proteins for NMR analysis [Xu et al., (1999)Proc. Natl. Acad. Sci. USA 96,388-393] Generation of substrates for protein arrays [Sun, L., et al., (2004) Biotechniques. 37:430-443.] Site specifically incorporating lipid moieties into a protein [Rak et al., (2003) Science 302, 646-650] For more information please refer to the detailed IMPACT FAQs.