Question

Which four statements about amino acids are true?a. Phe can undergo oxidation to form Tyr.b. The Leu side chain does not form hydrogen bonds with other amino acids.c. The form of glycine used by the human body is D‑glycine.d. Leucine has an overall charge at physiological pH (7.4).e. Methionine has one stereocenter (chiral center).f. Methionine is a thiol.g. Ser and Gln are polar amino acids.

Answer 1

f) methionine is a thiol.

g) Ser and Gln are polar amino acids.

e) Methionine has one stereocenter

a) Phe can undergo oxidation to form tyrosine.

Explanation:

Methionine is a sulphur containing amino acid. The sulphur is chemically linked by thiol ether.

Methionine has one chiral carbon, it means it has four different functional groups.

Phenylalanine uses Phenylalanine hydroxylase which performs oxidation, adding one oxygen to phenylalanine converting it into tyrosine.

The polar amino acids are found on the surface of proteins and they have side-chains which remains in water.