LAQV, FCT NOVA
Nitrite in Human Health
Host: José Moura
Nitric oxide radical (NO) is a signaling molecule involved in several physiological and pathological processes and a new nitrate-nitrite-NO pathway has emerged as a physiological alternative to the "classic" pathway of NO formation from L-arginine. Since the late 90s, it has become clear that nitrite can be reduced back to NO under hypoxic conditions and exert a significant cytoprotective action in vivo under challenging conditions. To reduce nitrite to NO, mammalian cells can use different metalloproteins that are present in cells to perform other functions, including several heme proteins and molybdenum-containing enzymes, comprising what we denominated as the "non-dedicated nitrite reductases". In this communication, we will review the current knowledge on the molybdenum-dependent "non-dedicated nitrite reductases", with focus on the xanthine oxidase and aldehyde oxidase (two of the most promising mammalian nitrite reducers), discussing the existing in vitro and in vivostudies to provide the current picture of the role of these enzymes on the NO metabolism in humans.
Luisa Maia received her Ph.D. degree in Pharmaceutical and Clinical Biochemistry from the Universidade de Lisboa (Portugal), for work on the characterization of molybdenum-containing enzymes relevant to human physiology and pathology. Presently, she is a researcher, at LAQV, in the "Biological Chemistry" group lead by José Moura. Her current research interests are focused on molybdenum-containing proteins, in aspects related with human health. She has been working with enzymes and small proteins containing molybdenum, from bacterial and mammalian sources, performing mostly kinetic and mechanistic characterizations, but also some studies to access the physiological role of the mammalian molybdoenzymes. Her recent efforts have been dedicated to the study of the new human nitrate-nitrite-nitric oxide pathway. In parallel, she is also studying formate dehydrogenases, aiming to use these molybdenum-containing enzymes to develop new biocatalysts for the conversion of the atmospheric carbon dioxide into added-value compounds. She has also been involved in the EPR spectroscopic characterization of different biological and inorganic systems, containing iron, copper, nickel and other metals.
Domains of specialization: Biochemistry, Bioinorganic Chemistry, Spectroscopy, Enzymology