試題詳解

2. The uncommon amino acid selenocysteine has an R group with the structure -CH₂-SeH ( ≈ 5). In an aqueous solution, pH = 7.0, selenocysteine would:
(A) be a fully ionized zwitterion with no net charge.
(B) be found in proteins as d-selenocysteine.
(C) never be found in a protein.
(D) be nonionic.
(E) not be optically active.