Kynurenine: A Promising Structural Motif for Diverse Biological Active Peptides

Kynurenine (Kyn), a key metabolite in the kynurenine pathway, has emerged as an important motif in natural peptides with diverse biological activities. This review explores the growing number of Kyn-containing peptides discovered and the importance of Kyn for biological activities. While daptomycin remains the most well-studied example, recent discoveries such as taromycins, gausemycins, and phakefustatin highlight the increasing recognition of Kyn as a component of bioactive natural peptides. Chemically modified Kyn, exemplified in peptides such as kynomycin and hexakynomycin, opens additional opportunities for drug development. Here, we highlight the functional importance of Kyn and encourage broader exploration of this underutilized but promising motif in natural product research.