Question

Which of the following is the earliest discovered amino acids?

• A. Glycine
• B. Methionine
• C. Phenylanine
• D. Asparagine

Answer 1

Answer: (A)

Glycine

Glycine is the simplest amino acid obtained by hydrolysis of proteins. It is sweet to taste and was one of the first amino acids to be isolated in 1820 from gelatin. It is resent in gelatin and silk fibroin and can be synthesized by the body from serine and threonine. Methionine is a sulphur containing amino acid which was isolated from casein in 1922. It is one of the essential amino acid which cannot be synthesized by the body but can be synthesized by microorganisms. Phenylalanine is also one of the essential amino acids which was first isolated in 1881 from lupine seedlings. Human haemoglobin is one of the richest sources of phenylalanine. Asparagine was first isolated from asparagus in 1932 and is widely distributed in plant proteins. It can be synthesized in the body from aspartic acid.

Thus, the correct answer is option A.