Amino acid present in Glutathione peroxidase:
The enzyme Glutathione Peroxidase is a selenoprotein requires Selenocysteine amino acid at its active site. Function of Glutathione peroxidase In RBCs, there is excess of oxygen which leads to generation of high amounts of H2O2. This H2O2 has to be destroyed to prevent oxidative damage in cell. This happens by following process: Enzyme involved in this process is Glutathione Peroxidase, It conves reduced glutathione (GSH) to oxidized form (GSSG) and in turn H2O2 gets reduced to H2O. Extra information: Selenocysteine is found in approximately 25 human proteins. Enzymes which use selenocysteine at their active sites are known as Selenoproteins e.g 1. Glutathione peroxidase and NOT Glutathione Reductase, which requires FAD (or Vit B2) 2. Thioredoxin reductase 3. Iodothyronine deiodinase Precursor amino acid for selenocysteine is serine. SelenoCysteine - 21st protein forming amino acid - UGA
Alanine
Selenocysteine
Cysteine
Serine
HAEM synth and porphyrias