Question

Anthranilic acid is an immediate precursor in the formation of

• A. Tyrosine
• B. Tryptophan
• C. Ornithine
• D. Methidine

Answer 1

The Correct Option is B

Anthranilic acid is a key intermediate in the biosynthesis of tryptophan, an essential amino acid. Let's go through the reasoning step-by-step to understand why tryptophan is the correct answer.

1. The biosynthesis of tryptophan, an aromatic amino acid, starts with chorismic acid. Anthranilic acid is derived from chorismic acid in this pathway.
2. Anthranilic acid undergoes further transformations to eventually form tryptophan. Specifically, it reacts with phosphoribosyl pyrophosphate to form N-(5'-phosphoribosyl)-anthranilate, which subsequently undergoes several enzymatic reactions to produce tryptophan.
3. This pathway is unique to tryptophan synthesis and does not occur in the formation of the other amino acids listed in the options (tyrosine, ornithine, or methidine).
4. Tyrosine is typically synthesized from phenylalanine or via the shikimic acid pathway, not directly involving anthranilic acid.
5. Ornithine and methidine (methionine) are synthesized via entirely different pathways, primarily involving the urea cycle and methionine cycle, respectively.

Therefore, the correct answer is tryptophan, as anthranilic acid is a direct precursor in its synthesis route.