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FRET Reporter Molecules for Identification of Enzyme Functions
Published in Grunwald Peter, Biocatalysis and Nanotechnology, 2017
Jing Mu, Hao Lun Cheong, Bengang Xing
Proteases, also known as proteolytic enzymes, are one of the most abundant enzyme families encoded by the human genome with more than 500 active members. Proteases catalyze the breakdown of proteins by hydrolysis of peptide bonds, an enzymatic reaction influential to many physiological and pathological processes such as cell proliferation, tissue remodeling, blood coagulation, wound repair, protein catabolism, inflammation, infection, and cancer progression, etc. (Turk et al., 2006; Drag et al., 2010). Generally, the mammalian proteases are classified as serine, cysteine, threonine, aspartic, and metalloproteases based on different catalytic mechanisms for substrate hydrolysis. Proteases interact with their peptide substrate through hydrogen binding, hydrophobic, and electrostatic reactions between the substrate side chain and active pockets, leading to hydrolysis of peptide bonds (Deu et al., 2012; Edgington et al., 2011). In the N-terminal serine, cysteine and threonine proteases, the acyl-enzyme intermediate was formed by nucleophilic attack of the catalytic side chain residue, whereas in the metalloproteinases and aspartic proteases the nucleophile is an activated water molecule, which results in acid–base catalysis (Fig. 13.6).
Impact of sedentarism due to the COVID-19 home confinement on neuromuscular, cardiovascular and metabolic health: Physiological and pathophysiological implications and recommendations for physical and nutritional countermeasures
Published in European Journal of Sport Science, 2021
Marco Narici, Giuseppe De Vito, Martino Franchi, Antonio Paoli, Tatiana Moro, Giuseppe Marcolin, Bruno Grassi, Giovanni Baldassarre, Lucrezia Zuccarelli, Gianni Biolo, Filippo Giorgio di Girolamo, Nicola Fiotti, Flemming Dela, Paul Greenhaff, Constantinos Maganaris
The combination of low energy intake and physical inactivity, typically observed in bedridden sick patients, may lead to protein-energy malnutrition, skeletal muscle and fat mass loss, increased complications and, possibly, poor clinical outcome (Ritz & Elia, 1999). Poor energy intake is often observed in astronauts during space missions in microgravity. Astronauts may exhibit alterations in body composition and efficiency commonly observed in bedridden patients (Ritz & Elia, 1999; Wade et al., 2002; Wilson & Morley, 2003). In addition to decreased energy intake, physical inactivity is characterised by anabolic resistance, i.e. a decreased ability to utilise dietary amino acids for synthesis of body proteins. Anabolic resistance to dietary amino acids in association with muscle unloading leads to protein catabolism (Biolo et al., 2004; Ferrando, Lane, Stuart, Davis-Street, & Wolfe, 1996; Stein, Leskiw, Schluter, Donaldson, & Larina, 1999; Stevenson, Giresi, Koncarevic, & Kandarian, 2003) and, ultimately, to muscle dysfunction and atrophy (di Prampero & Narici, 2003; Jackman & Kandarian, 2004). Major triggers of anorexia and decreased food intake in bedridden patients, sedentary healthy humans and astronauts are cytokines and systemic inflammation, disruption of circadian rhythms, alteration in gastrointestinal functions and alterations in neuroendocrine mediators (Da Silva et al., 2002; Stein et al., 1999). Evidence indicates that anorexia in astronauts during long-term space flight can lead to 20–30% decrease in food intake as compared to pre- and/or post-flight conditions (Da Silva et al., 2002; Stein et al., 1999; Wade et al., 2002). By this mechanism, the body weight of an astronaut can decrease by about 0.5 kg for each week spent in space (Wade et al., 2002).
Application of Raman spectroscopy to diagnose the metabolic state of volleyball and soccer players through the identification of urine components
Published in Instrumentation Science & Technology, 2020
Fernando Bernal-Reyes, Mónica Acosta-Elias, Alexel J. Burgara-Estrella, Osiris Álvarez-Bajo, Omar I. Gavotto-Nogales, Francisco J. Antunez-Dominguez, Lucia Placencia-Camacho, Héctor M. Sarabia-Sainz
According to the Raman and concentration analyses, the excretion of urea changed with exercise. The production of urea is due to the increase in protein catabolism and gluconeogenesis in response to exercise.[27] Resistance exercises induce the highest protein degradation.[28]