Hi, this problem is puzzling me since all options seem false for my understanding:
The uncommon amino acid selenocysteine has an R group with the structure CH2SeH (pKa ≈ 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
I think it has a negative net charge since pKa<pH and its ionic (no a,d). It has a optically active alfa carbon (no e). All proteins have l-form amino acids (no b). Selenocysteine is found in some proteins though its not common (no c).
Where am I wrong?
ps. this is not a homework
