Which amino acid does not include post translational modification?
(A) Selenocystiene (B) Triiodothyronine (C) Hydroxy-proline (D) Hydroxy-lysine
(A) Selenocysteine (21st amino acid) & Pyrrolysine (22nd amino acid) Formed by co-translational modification Not by post-translational modifications. Selenocysteine and Pyrrolysine 21st amino acid-Selenocysteine- UGA 22nd amino acid - Pyrrolysine - UAG Both UGA, UAG are stop codon but co-translational modification can give rise to amino acid selenocysteine and pyrrolysine. co-translational modification. Enzymes that use selenocysteine as their active sites are called Seleno Proteins. Selenocysteine containing proteins: Glutathione peroxidase Thioredoxin reductase selenoprotein P 5' deiodinases