Selenomethionine: A Pink Trojan Redox Horse with Implications in Aging and Various Age-Related Diseases

Abstract

Selenium is an essential trace element. Although this chalcogen forms a wide variety of compounds, there are surprisingly few small-molecule organic selenium compounds (OSeCs) in biology. Besides its more prominent relative selenocysteine (SeCys), the amino acid selenomethionine (SeMet) is one example. SeMet is synthesized in plants and some fungi and, via nutrition, finds its way into mammalian cells. In contrast to its sulfur analog methionine (Met), SeMet is extraordinarily redox active under physiological conditions and via its catalytic selenide (RSeR’)/selenoxide (RSe(O)R’) couple provides protection against reactive oxygen species (ROS) and other possibly harmful oxidants. In contrast to SeCys, which is incorporated via an eloquent ribosomal mechanism, SeMet can enter such biomolecules by simply replacing proteinogenic Met. Interestingly, eukaryotes, such as yeast and mammals, also metabolize SeMet to a small family of reactive selenium species (RSeS). Together, SeMet, proteins containing SeMet and metabolites of SeMet form a powerful triad of redox-active metabolites with a plethora of biological implications. In any case, SeMet and its family of natural RSeS provide plenty of opportunities for studies in the fields of nutrition, aging, health and redox biology.

Comparative study of the effects of selenium nanoparticles and selenite on selenium content and nutrient quality in soybean sprouts

“…On the one hand, SeCys 2 , SeMet and MeSeCys were found in both SeNPs and selenite-treated soybean sprouts in this study. Given the efficiency of these three Se forms in safeguarding human health (Schoenmakers and Chatterjee, 2020;Nasim et al, 2021), this study establishes SeNPs as a viable Se source for producing Se-enriched soybean sprouts. On the other hand, Se 6+ was only found in soybean sprouts treated with SeNPs (Table 1).…”

Immunomodulatory and Anti-Inflammatory Properties of Selenium-Containing Agents: Their Role in the Regulation of Defense Mechanisms against COVID-19

“…SLM also protects lung tissues from the toxic effects of ionizing radiation by decreasing the expression of the DUOX 1 and 2, the α-1 subunit of the IL-4 receptor. SLM can modulate HOCl-induced damage, and inhibits single-stranded RNA and DNA viruses, including SARS-COV-2 [40,101,[111][112][113][114]. MSC recovers the consequences of elaidic acid-induced inflammation by decreasing the expression of ICAM-1, E-selectin, IL-8, and NO production [119].…”

“…As the CH3-Se group in SLM is more hydrophobic than the CH3-S group in methionine, access to the substrate can be impaired by changing the kinetic parameters. In general, these proteins and enzymes are also good and are often catalytic antioxidants [101]. As SLM is a powerful antioxidant capable of protecting cells from oxidative stress and maintaining redox homeostasis, it is able to exert its activity in all pathophysiological processes associated with oxidative stress, such as inflammation, microbial and viral infections, oncogenesis, coronary artery disease, neurodegenerative diseases, and many others.…”

“…SLM has been reported to inhibit porcine circovirus type 2 (PCV2) in vitro in a concentration-dependent manner ranging from 2 to 16 µM. PCV2 is a single-stranded DNA virus associated with several complications including porcine dermatitis nephropathy syndrome (PDNS), post-weaning multisystem wasting syndrome (PMWS), porcine respiratory disease complex (PRDC), type A2 congenital tremor (CT), and reproductive obstruction pregnant sows [101]. In these studies, attention is drawn to the large differences in the concentrations of SLM required for antiviral activity against single-stranded RNA and DNA viruses, which may indicate some selectivity with respect to the type of viruses.…”

Thyroidal and Extrathyroidal Requirements for Iodine and Selenium: A Combined Evolutionary and (Patho)Physiological Approach

“…Selenomethionine is, compared with methionine, extraordinarily redox active under physiological conditions, providing protection against reactive oxygen species and other possibly harmful oxidants. Selenomethionine might be the 22nd amino acid needed in proteins with functions of its own [ 18 ]. Selenotoxicity is, however, much more complex as it has a number of interacting substances [ 19 ].…”