Techniques for the determination of dipeptidyl peptidase IV and screening of its inhibitors

Dipeptidyl peptidase IV (DPP-IV), an important member of the serine hydrolase family, plays a core regulatory role in various physiological and pathological processes because of its unique broad-spectrum substrate specificity. DPP-IV-mediated proteolytic processing of endogenous peptide substrates serves as a fundamental regulatory mechanism governing physiological processes. An in-depth exploration of the enzymatic characteristics and mechanisms regulating DPP-IV activity will not only provide a theoretical basis for revealing the molecular pathogenesis of related diseases but also contribute to the construction of a complete disease regulatory network map. Furthermore, the development of specific DPP-IV inhibitors constitutes a key strategy for innovative therapy, holding significant promise for clinical translation. This review provides a comprehensive comparison of the applications, merits, and limitations of DPP-IV detection at the messenger RNA (mRNA), protein, and functional levels, along with an in-depth analysis of how DPP-IV enzymatic activity assessment profoundly impacts disease pathogenesis, progression, and therapeutic interventions. Particular emphasis is placed on the superior performance of probes based on drugs and optical substrates (e.g., for fluorescence and bioluminescence) in the functional determination of DPP-IV. Through metabolic phenotyping, we further summarize drug screening systems that target DPP-IV across multiple biological levels, including recombinant proteins (e.g., proteins derived from humans, animals, and gut bacteria), tissues, cells, human organ-on-a-chip models, and whole-animal studies. Furthermore, this review comprehensively evaluates both synthetic and natural DPP-IV inhibitors. Additionally, systematic investigations of their structure‒activity relationships (SARs) provide a rational foundation for developing novel inhibitors with enhanced efficacy and safety.