Question

The amino acid tryptophan is the precursor for the synthesis of?

Answer 1

Amino acids are the basic structural unit that makes up proteins. Amino acids are organic compounds that contain Amino (-$NH_2$ ), carboxyl (-COOH) functional groups, and a side chain of carbon (R group) which is specific to each amino acid. The key components of amino acids are carbon(C), hydrogen(H), oxygen(O), and nitrogen(N); sometimes other elements can also be present in the side chains of some amino acids.

Complete answer:
Precursor amino acids are those amino acids that give different compounds after some reactions.
Tryptophan is an essential amino acid that cannot be synthesized inside the human body so it has to be taken by other sources.
Tryptophan is alpha-amino acid, it contains an alpha-amino group, a carboxylic acid group, and a side chain indole.
It is a nonpolar amino acid.
There are two types of tryptophan-
1. L-tryptophan
2. D-tryptophan

Tryptophan is a precursor to the neurotransmitter serotonin, the hormone melatonin, and vitamin B3.
Tryptophan is encoded by the codon UGG.
At physiological pH, Tryptophan is a zwitterion where the amino group is protonated and the carboxylic acid is deprotonated.
Tryptophan is the building block of protein synthesis.

Note:
Serotonin is synthesized by Tryptophan hydroxylase, whereas melatonin is synthesized from serotonin via N-acetyltransferase and 5-hydroxy indole-O-methyltransferase enzymes. Niacin (vitamin B3) is synthesized from tryptophan via kynurenine and quinolinic acid. Auxins are also synthesized from tryptophan.