All are true about selenocystiene EXCEPT:: (A) Considered as 21stAmino acid, (B) Coded by UGA, (C) Occurs in glutathione peroxidase, (D) Made of cysteine and methionine
Answer is D. 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 2. Thioredoxinreductase 3. Iodothyroninedeiodinase Precursor amino acid for selenocysteine is serine. (not cysteine or methionine) Coded by UGA codon