Glutathione peroxidase activity and redox potential determination of human selenoproteins: Selenoprotein M and selenoprotein W

Glutathione Peroxidases (GPXs) are a family of selenium-containing antioxidant enzymes that catalyze the reduction of a variety of hydroperoxides (ROOH) in the presence of reduced glutathione (Scheme 1).

Scheme 1. GPx catalyzed reduction of hydroperoxides

The human body contains twenty five selenoproteins,¹ yet the biological function of many of these proteins remains unclear or poorly studied. Specifically, human selenoprotein M (SELM) and selenoprotein W (SELW) are selenoproteins which is still biologically uncharacterized and their function is not established. Human SELM is an endoplasmic reticulum (ER) selenoprotein which is most abundant in the brain,² suggesting an important role in the nervous system. The other selenoprotein SELW is a small cytosolic protein which is highly conserved in mammals, and is one of the most highly expressed selenoproteins.³ In order to understand the function of SELM and SELW, previously our group have presented the total chemical synthesis of these two selenoproteins by utilizing SPPS and native chemical ligation.⁴

Furthermore, herein, we are presenting the antioxidant activities and redox potential determination of these two selenoproteins SELM and SELW. The antioxidant activities have been performed spectrophotometrically using coupled reductase assay. Here we report our preliminary data for the antioxidant activities of SELM and SELW, in which it was compared to natural bovine GPx enzyme and highly studied synthetic GPx mimic, ebselen.

References:

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