Question

A non-protein amino acid is

• A. Hydroxyproline
• B. Cystine
• C. Gamma-aminobutyric acid
• D. Hydroxylysine

Answer 1

The correct option is C Gamma-aminobutyric acid

A non protein amino acids are the amino acids which are not naturally encoded by the genetic code of an organism. gamma-Aminobutyric acid is a chief inhibitory neurotransmitter. It is responsible for a muscle tone. It is a non-protein amino acid as it do not encode any protein naturally. It is also known as non standard protein. It is formed by the post translational modification.

So, the correct answer is option C.