Glycine - Structure of Glycine, Properties of Glycine, Practice problems, Frequently asked questions - FAQs

Have you ever played with building blocks when you were kid? I guess many of you have seen that game, in which a child combines blocks and then at the end he would be able to create a building or a proper house. But if it is not connected properly then the kid will not be able to build.

Why do you think I am telling you such things about the building blocks game? It is related to our topic which we are going to study now!

We all eat chapati. But what is that chapati made up of? Dough, right? But wait what is that doubt made up of? Flour, right? Now from where do we get this flour? Wheat, right? So we can see the chapati which we are ultimately eating for our food is actually made of small components. Like in dough, flour is its building block.

In chemistry also, we may see this process happening in various areas as well. Let's make a connection to amino acids. Amino acids, which serve as the building blocks for proteins like flour do for dough, are what make up proteins.

Peptide linkages enable the amino acids to build long chains of peptides; these peptides then join and go through conformational changes to form the final polypeptide structure, or protein. There are many various kinds of amino acids, and in this article we'll talk about glycine, one of them.

Let's examine what glycine is and its applications!

Table of content:

Glycine
Structure of Glycine
Properties of Glycine
Uses of Glycine
Practice problems
Frequently asked questions - FAQs

Glycine:

One of the earliest amino acids to be found, glycine, was taken out of the protein gelatin in 1820. Because of its sweet flavor, the amino acid receives its name from the Greek word glyco, which means sugar. Of the twenty amino acids, glycine is the most fundamental. The letters Gly or G stand for it.

All codons that start with the nitrogenous bases GG encode the amino acid glycine. Simply said, the codes for glycine are GGU, GGC, GGA, and GGG. Glycine is a non-essential amino acid that is generated in the body from the amino acid L-Serine. Despite being quite small, it plays a vital role in a number of structural polypeptides. The loops of a polypeptide structure contain large amounts of the two amino acids glycine and proline.

Structure of Glycine:

If we talk about the structure of amino acids in general, the basis or backbone of each amino acid is the same. An amine group (-NH₂) makes up the backbone with a carboxyl group attached to a central carbon. A carbon atom that is single attached to a hydroxyl group and double linked to oxygen is known as a carboxyl group (-COOH). The core carbon is bonded to hydrogen on one side and a side-chain or R group on the other because carbon can establish four bonds.

Because the side chain is the sole part of an amino acid that varies, it serves as the only characteristic feature of each amino acid. Through their backbone, amino acids are connected. One amino acid's amino group is joined to the carboxyl group of another. This association creates a peptide bond, and when several amino acids are joined together, a polypeptide is produced.

Of all the human amino acids, glycine has the smallest and most basic structure. One of the simplest amino acids is glycine, which has a side chain made up of a hydrogen atom, an amino group, and a carboxylic group. The molecular formula for glycine is C₂H₅NO₂. Due to the fact that it contains just one tiny hydrogen atom as a side chain, it is the smallest amino acid and has the greatest rotational mobility. This explains why glycine and proline, which has a cyclic side chain, are crucial for the folding of proteins.

Glycine is achiral because, as can be seen in the above image, not all of the four side groups connected to the carbon atom are unique. All other amino acids have enantiomers since they contain at least one chiral carbon atom, with the exception of glycine. Due to its lack of chirality, glycine has no enantiomeric structures. Glycine is non polar when it form polypeptide bond whereas it acts as a polar molecule when it form Zwitter ion as shown below.

Properties of Glycine:

A crystalline substance with a sweet flavor and a molecular weight of 75.066 u..
Glycine has a density of 1.161 g/cm3 at 20℃.
Water readily dissolves glycine.
Since it starts to break down at high temperatures around 233℃, its melting point cannot be calculated.
The body converts L-Serine, another amino acid, into glycine.

Uses of Glycine:

It is used to treat conditions like benign prostatic hyperplasia, schizophrenia, stroke, and a few other uncommon inherited metabolic problems.
It is used as a sweetener or flavor enhancer. Glycine can be found in some protein-rich beverages and food supplements.
Glycine, which aids in enhancing stomach absorption, is present in some medication formulations.
In analgesics, antacids, antiperspirants, cosmetics, toiletries, etc., this serves as a buffering agent.
It serves as an intermediary in the production of several chemical products and is also utilized in the production of the herbicide glyphosate.

Practice problems:

Q1: Which of the given codes are correct for Glycine?

GGU, GGC, GGA, and GGG.
AAA and AAG
UCU, UCC, UCA, UCG, AGU and AGC
None of the above

Answer: (A)

Solution: The codes for glycine are GGU, GGC, GGA, and GGG. Glycine is a non-essential amino acid that is generated in the body from the amino acid L-Serine.

Q2: Which of the given statements about Glycine is correct?

glycine is a non-essential amino acid
When it forms a polypeptide bond, glycine is nonpolar
glycine has the molecular formula C₂H₅NO₂
All of the above

Answer: (D)

Solution: Glycine is a non-essential amino acid, so the body can synthesize it from other amino acids. The body only produces a tiny quantity of glycine very slowly, which can occasionally be an issue. The amino acid serine can be converted by the body into glycine. The chemical compound glycine has the molecular formula C₂H₅NO₂. Moreover, When it forms a polypeptide bond, glycine is nonpolar; but, when it forms a Zwitter ion, it behaves as a polar molecule.

Q3: Not all of the four side groups connected to the carbon atom are unique in Glycine. So, Glycine is:

Chiral
Achiral
Polar
None of the above

Answer: (B)

Solution: Glycine is achiral because, as can be seen in the above image, not all of the four side groups connected to the carbon atom are unique. All other amino acids have enantiomers since they contain at least one chiral carbon atom, with the exception of glycine as shown below.

Q4: Which of the following statements is incorrect about Glycine?

It is obtained from hydrolysis of proteins
It is produced in the body from the amino acid L-Arginine
Some medicine formulations contain glycine, which helps to improve stomach absorption.
Glycine is a non-essential amino acid

Answer: (B)

Solution: Glycine is produced in the body from the amino acid L-Serine and therefore glycine is a non-essential amino acid.

Frequently asked questions-FAQs:

Q1: What is the importance of Glycine?
Answer: The most fundamental amino acid, glycine, is essential for numerous biological processes and functions. It also serves as the spinal cord's and the brain stem's main neurotransmitter inhibitor, as well as an anti-inflammatory, cytoprotective, and immunological modulator.

Q2: What exactly does glycine consist of?
Answer: With two carbon atoms, five hydrogen atoms, one nitrogen atom, and two oxygen atoms, glycine is an organic molecule. One of the 20 widely occurring amino acids in animal proteins, it is. The chemical compound glycine has the molecular formula C₂H₅NO₂.

Q3: What function does glycine perform in the body?
Answer: Glutathione, porphyrins, purines, haem, and creatine are just a few of the crucial metabolites that create glycine. In addition to its range of antioxidant, anti-inflammatory, cryoprotective, and immunomodulatory actions in peripheral and neurological tissues, glycine is a neurotransmitter in the central nervous system.

Q4: Is glycine polar or nonpolar?
Answer: When it forms a polypeptide bond, glycine is nonpolar; but, when it forms a Zwitter ion, it behaves as a polar molecule.

Q5: Glycine is hydrophilic in nature, why?
Answer: Because the minimum side chain has one hydrogen atom, it is said to have a hydrophilic character. When combined with carbohydrates, it enhances lean growth and promotes rapid recovery. It aids in the synthesis of proteins in the body.