The emerging role of dipeptidyl peptidase 3 in pathophysiology

Dipeptidyl peptidase 3 (DPP3), a zinc-dependent aminopeptidase, is a highly conserved enzyme among higher animals. The enzyme cleaves dipeptides from the N-terminus of tetra- to decapeptides, thereby taking part in activation as well as degradation of signalling peptides critical in physiological and pathological processes such as blood pressure regulation, nociception, inflammation and cancer. Besides its catalytic activity, DPP3 moonlights as a regulator of the cellular oxidative stress response pathway, e.g., the Keap1-Nrf2 mediated antioxidative response. The enzyme is also recognized as a key modulator of the renin-angiotensin system. Recently, DPP3 has been attracting growing attention within the scientific community, which has significantly augmented our knowledge of its physiological relevance. Herein, we review recent advances in our understanding of the structure and catalytic activity of DPP3, with a focus on attributing its molecular architecture and catalytic mechanism to its wide-ranging biological functions. We further highlight recent intriguing reports that implicate a broader role for DPP3 as a valuable biomarker in cardiovascular and renal pathologies and furthermore discuss its potential as a promising drug target

The possible role of a bacterial aspartate β-decarboxylase in the biosynthesis of alamandine

The understanding of the renin-angiotensin system (RAS) has significantly expanded over the last two decades. The elucidation of angiotensin-converting enzyme 2 (ACE2) that converts angiotensin (Ang) II into Ang (1-7) led to the discovery of the cardio-protective axis of the RAS. In addition, novel components of the system, Angiotensin A (Ang A) and alamandine have been identified. Like Ang (1-7), alamandine is a vasodilator and can counteract the effects of Ang II by increasing nitric oxide release from the endothelium and decreasing nicotinamide adenine dinucleotide phosphate oxidase (NADPH)-related superoxide production. Theoretically, alamandine can be derived from Ang (1-7) by decarboxylation of the N-terminal aspartic acid residue to alanine, but the enzyme responsible for this is still unknown. To date, no human or mammalian enzyme with the assigned decarboxylase activity has been identified. However, several bacterial enzymes capable of converting aspartate to alanine have been reported. Therefore, we hypothesize that a bacterial enzyme, most likely present in the microbiome of the gastrointestinal tract, the heart, or systemic circulation could metabolize Ang II, and/or Ang 1-7, to Ang A and alamandine, respectively, in mammals

Novel Methods for the Quantification of Dipeptidyl Peptidase 3 (DPP3) Concentration and Activity in Human Blood Samples

BACKGROUND: The ubiquitously expressed dipeptidyl peptidase 3 (DPP3) is involved in protein metabolism, blood pressure regulation, and pain modulation. These diverse functions of DPP3 are attributed to the degradation of bioactive peptides like angiotensin II. However, because of limitations in currently available assays for determination of active DPP3 in plasma, the exact physiological function of DPP3 and its role in the catabolism of bioactive peptides is understudied. Here, we developed 2 assays to specifically detect and quantify DPP3 protein and activity in plasma and validated DPP3 quantification in samples from critically ill patients. METHODS: Assay performance was evaluated in a sandwich-type luminometric immunoassay (LIA) and an enzyme capture activity assay (ECA). DPP3 plasma concentrations and activities were detected in a healthy, population-based cohort and in critically ill patients suffering from severe sepsis and septic shock. RESULTS: The DPP3-LIA and DPP3-ECA show an almost ideal correlation and very similar and robust performance characteristics. DPP3 activity is detectable in plasma of predominantly healthy subjects with a mean (±SD) of 58.6 (±20.5) U/L. Septic patients show significantly increased DPP3 plasma activity at hospital admission. DPP3 activities further increase in patients with more severe conditions and high mortality risk. CONCLUSION: We developed 2 highly specific assays for the detection of DPP3 in plasma. These assays allow the use of DPP3 as a biomarker for the severity of acute clinical conditions and will be of great value for future investigations of DPP3's role in bioactive peptide degradation in general and the angiotensin II pathway in specific

The emerging role of dipeptidyl peptidase 3 in pathophysiology

Dipeptidyl peptidase 3 (DPP3), a zinc-dependent aminopeptidase, is a highly conserved enzyme among higher animals. The enzyme cleaves dipeptides from the N-terminus of tetra- to decapeptides, thereby taking part in activation as well as degradation of signalling peptides critical in physiological and pathological processes such as blood pressure regulation, nociception, inflammation and cancer. Besides its catalytic activity, DPP3 moonlights as a regulator of the cellular oxidative stress response pathway, e.g., the Keap1-Nrf2 mediated antioxidative response. The enzyme is also recognized as a key modulator of the renin-angiotensin system. Recently, DPP3 has been attracting growing attention within the scientific community, which has significantly augmented our knowledge of its physiological relevance. Herein, we review recent advances in our understanding of the structure and catalytic activity of DPP3, with a focus on attributing its molecular architecture and catalytic mechanism to its wide-ranging biological functions. We further highlight recent intriguing reports that implicate a broader role for DPP3 as a valuable biomarker in cardiovascular and renal pathologies and furthermore discuss its potential as a promising drug target.ISSN:1742-464XISSN:1742-465

The scope of flavin-dependent reactions and processes in the model plant Arabidopsis thaliana

Eggers, Reinmar, Jammer, Alexandra, Jha, Shalinee, Kerschbaumer, Bianca, Lahham, Majd, Strandback, Emilia, Toplak, Marina, Wallner, Silvia, Winkler, Andreas, Macheroux, Peter (2021): The scope of flavin-dependent reactions and processes in the model plant Arabidopsis thaliana. Phytochemistry (112822) 189: 1-42, DOI: 10.1016/j.phytochem.2021.112822, URL: http://dx.doi.org/10.1016/j.phytochem.2021.11282