In our ongoing efforts to facilitate nucleoside synthesis with nucleoside phosphorylases, we serendipitously discovered that nucleoside phosphorylases (NPs) can furnish N7-xanthosine (N7X, Figure ), the "non-native" 8 glycosylation regioisomer of xanthosine. NPs are ubiquitous across all kingdoms of life and known for their high selectivity and robustness. 9-11 These enzymes are primarily tasked with recycling nucleosides by cleaving them into the corresponding nucleobase and ribose 1-phosphate (Rib1P), which is funneled back into the primary carbon metabolism. As their transformations are tightly thermodynamically controlled, they also catalyze the corresponding reverse reactions (glycosylations) and thereby maintain balanced physiological concentrations of nucleosides and nucleobases. Any failure to do so generally results in disease (e.g. immune disorders). Thus, modern pyrimidine and purine NPs are under considerable selection pressure to execute their physiological tasks fast and selectively.