Biochemistry - Structure and Properties of Amino Acids - Discussion

Cystein is hydrophilic, it can lose the proton in the side chain and become neg charged at higher pH.

I think the correct answer is B not C because the side chain of cysteine is hydrophillc not hydrophobic.

@Jordan, you are wrong, lecture notes say hydrophobic. Get it right.

I think B is correct because the side chain is polar.

The correct answer will be B that because the following charged:

Arginine - Arg - R.
Lysine - Lys - K.
Aspartic acid - Asp - D.
Glutamic acid - Glu - E.

Polar (may participate in hydrogen bonds)hydophilic:

Glutamine - Gln - Q.
Asparagine - Asn - N.
Histidine - His - H.
Serine - Ser - S.
Threonine - Thr - T.
Tyrosine - Tyr - Y.
Cysteine - Cys - C.
Methionine - Met - M.
Tryptophan - Trp - W.

Hydrophobic (normally buried inside the protein core):

Alanine - Ala - A.
Isoleucine - Ile - I.
Leucine - Leu - L.
Phenylalanine - Phe - F.
Valine - Val - V.
Proline - Pro - P.
Glycine - Gly - G.

Yea this is definitely wrong. Cysteine side chain is sulfhydryl which is extremely electronegative causing the molecule to be very polar and thus very hydrophilic. The answer is B.

The sulphur containing amino acids (cysteine and methionine) are generally considered to be nonpolar and hydrophobic.

I think B too because C has that sulfhydryl group which can form H bonds.

You can correct me if am wrong.

Cysteine is a polar uncharged amino acid so, its a hydrophobic and due to the sulphur it is highly reactive and can form cystine.

The correct answer is B) SF is hydrophilic.