Assessment of Renalase Activity on Catecholamines Degradation

Janete Quelhas-Santos1, *, Benedita Sampaio-Maia2, Fernando Remião3, Paula Serrão4, Isabel Soares-Silva1, Gary V. Desir5, Manuel Pestana1, 6
1 Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Portugal & Nephrology and Infectious Diseases Research and Development Group, INEB, University of Porto, Alameda Prof. Hernâni Monteiro, 4200-319, Porto, Portugal
2 Faculty of Dental Medicine, University of Porto, Rua Dr. Manuel Pereira da Silva, 4200-392 Porto, Portugal
3 REQUIMTE, Laboratório de Toxicologia, Departamento de Ciências Biológicas, Faculdade de Farmácia, Universidade do Porto, Rua de Jorge Viterbo Ferreira, nº228, 4050-313 Porto, Portugal
4 Department of Pharmacology and Therapeutics, Faculty of Medicine, University of Porto, Alameda Prof. Hernâni Monteiro, 4200-319, Porto, Portugal
5 Yale University School of Medicine, Department of Medicine, New Haven, & VACHS Medical Center, West Haven, CT, USA
6 Hospital de S. João EPE, Alameda Prof. Hernâni Monteiro, 4200-319, Porto, Portugal

© 2015 Quelhas-Santos et al.

open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International Public License (CC-BY 4.0), a copy of which is available at: This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

* Address correspondence to this author at the Nephrology and Infectious Diseases Research and Development Group, INEB & Hospital de S. João EPE, University of Porto, Alameda Prof. Hernâni Monteiro, 4200-319, Porto, Portugal; Tel: 351-22-5512100; Fax: 351-22-5512228; E-mail:


Renalase was recently described as a new flavoprotein that functions as FAD/NADH-dependent oxidase and, in contrast to other monoamine oxidases, is secreted into plasma and urine. Recombinant renalase was found to exert powerful and rapid hypotensive effects when administered intravenously on rats and this was suggested to be mediated by circulating catecholamines degradation. However there is no concrete evidence that directly supports the hypothesis that renalase metabolizes catecholamines. In this study we aimed to evaluate the catecholamines-degrading renalase activity by three different technical approaches: 1) Amplex Red Monoamine Oxidase Assay, which evaluates the rate of resaruzin reduction by renalase oxidative activity; 2) assessment of catecholamines consumptions by high-pressure liquid chromatography (HPLC) with electrochemical-detection (ED) and 3) assessment of product formation by HPLC with photodiode array-detection (DAD). Using the Amplex Red MAO Assay, all three catecholamines were degraded by recombinant renalase overtime, being adrenaline the preferred substrate, followed by noradrenaline and dopamine. In addition using HPLC-ED, it was observed the consumption of all three catecholamines by recombinant renalase, which were oxidized to the correspondent aminochromes, as observed by DAD. However the role of renalase as catalyzer of aminochromes production is still undefined. In summary, the data presented in this study propose by different methodologies the involvement of renalase in catecholamine metabolization.

Keywords: HoAminochromesments, catecholamines, monoamine oxidase activity, renalase.