Tryptophan | Properties | Biosynthesis | Function.....

 Tryptophan Amino Acid

Introduction

It is an essential amino acid. Tryptophan contain α-amino acid that is used in the biosynthesis of proteins. Tryptophan contains  α-amino group and α-carboxylic acid group. A side chain indole, making it a non-polar aromatic amino acid. It is essential in humans, meaning that the body cannot synthesize it and it must be obtained from the diet. Tryptophan is also a precursor to the neurotransmitter serotonin, the hormone melatonin, and vitamin B3. It is encoded by the codon UGG.

Tryptophan is a zwitterion at physiological pH where the amino group is protonated and the carboxylic acid is deprotonated.

 History-

Tryptophan was first isolated in 1901, from the milk protein casein, by Sir Frederick Gowland Hopkins. By feeding mice a diet devoid of tryptophan, he was later able to demonstrate that it is essential for animal life. As well, he demonstrated that tryptophan and several other amino acids cannot be manufactured in the body and must be obtained from the diet. He was awarded the Nobel Prize for his discovery of vitamins, produced by amino acids like tryptophan.

Properties :-

Chemical formula :- C₁₁H₁₂N₂O₂

Molar mass :- 204.229 g·mol−1

Solubility in water :- Soluble: 0.23 g/L at 0 °C, 11.4 g/L at 25 °C, 17.1 g/L at 50 °C, 27.95 g/L at 75 °C

Thermodynamic data :- Phase behaviour (solid–liquid–gas) 

Structure-

Sources-

Tryptophan is present in most protein-based foods or dietary proteins. It is particularly plentiful in chocolate, oats, dried dates, milk, yogurt, cottage cheese.  Contrary to the popular belief  that cooked turkey contains an abundance of tryptophan. The tryptophan content in turkey is typical of poultry

Biosynthesis-

It is an essential amino acid, tryptophan is not synthesized from simpler substances in humans and other animals, so it needs to be present in the diet in the form of tryptophan-containing proteins. Plants and microorganisms commonly synthesize tryptophan from shikimic acid or anthranilate, anthranilate condenses with phosphoribosylpyrophosphate (PRPP), generating pyrophosphate as a by-product. The ring of the ribose moiety is opened and subjected to reductive decarboxylation, producing indole-3-glycerol phosphate; this, in turn, is transformed into indole. In the last step, tryptophan synthase catalyzes the formation of tryptophan from indole and the amino acid serine.

Function-

Amino acids, including tryptophan, are used as building blocks in protein biosynthesis. 

Proteins are required to sustain life.

Many animals (including humans) cannot synthesize tryptophan: they need to obtain it through their diet, making it an essential amino acid.

Tryptophan is among the less common amino acids found in proteins, but it plays important structural or functional roles whenever it occurs.

Tryptophan and tyrosine residues play special roles in "anchoring" membrane proteins within the cell membrane.

Tryptophan, among with other aromatic amino acids, is also important in glycan-protein interactions.

SUBSCRIBE FOR MORE INFORMATION........!