Selenium is present in which enzyme -

Ans. is 'b' i.e., Glutathione peroxidase * Selenium is a trace element that acts as a cofactor for the following enzymes1. Glutathione peroxidase# Glutathione is an antioxidant which is effective in detoxifying hydrogen peroxideH2O2 + 2GSH -> GS - SG + 2H2O# The hydrogen atoms from GSH get added to hydrogen peroxidase to form water. To start with, the source of two hydrogen atoms is selenol side chain of glutathione peroxidase2. Thioredoxinereductase# It generates reduced thioredoxin, a dithiol that serves as an electron source for peroxidases and also the important reducing enzyme ribonucleotidereductase that makes DNA precursors from RNA precursors3. Deiodinase# All three deiodinases Dl, D2, D3 need selenium as a cofactor. These deiodinases help in the conversion ofT4 to T3 or rT3.