Question

Taurine (2-aminoethanesulfonic acid) is sometimes called an amino acid.

(a) Explain why this designation is not valid. (b) From which of the 20 standard amino acids is taurine derived? Describe the chemical change(s) that occurred.

Short answer

a. This designation is invalid because of the lack of a carboxyl group. Amino and carboxyl groups are the main functional group of amino acids, the identification groups.

b. Cysteine will convert to taurine in the presence of enzymes cysteine dioxygenase and hypotaurine dehydrogenase.

Step-by-step solution

(a) Reason behind the statement

Taurine is sometimes called an essential amino acid. But this title is invalid because of the lack of a carboxyl group. Instead of the carboxyl group, the sulfonic acid group is present.

(b) Precursor amino acid responsible for taurine synthesis

Taurine, commonly called 2-aminoethanesulfonic acid is naturally derived from the cysteine amino acid.

Cysteine will convert to sulfinic acid using the cysteine dioxygenase enzyme. Then the acid will convert to hypotaurine by decarboxylation in the presence of sulfinoalanine decarboxylase. Taurine will result from the enzymatic action of hypotaurine dehydrogenase.