The renaissance in the use of peptides and proteins as therapeutic agents has led to significant demand for new technologies to rapidly and efficiently access these biomolecules, especially those bearing tailor-made modifications to maximize specificity and activity, or to probe biological function (e.g. through incorporation of post-translational modifications, fluorophores and/or imaging reagents).1 We have recently developed a number of synthetic and semi-synthetic technologies that enable efficient production of proteins bearing homogeneous post-translational modifications at pre-determined sites.2,3 This talk will highlight the utility of these technologies for generating: (1) bioactive modified proteins under continuous flow conditions,3 (2) mirror image proteins4 and (3) proteins with site-specific and homogeneous post-translational modifications using ligation5,6 or late-stage photocatalysis or electrochemistry.7,8