Difference between Amino Acid and Protein

Table of Contents

What Are Amino Acids?

Amino acids are organic compounds that are composed of an amino and a carboxylic group with a side chain (designated as R) unique to all amino acids. The amino acids are building blocks of proteins. 20 amino acids have been identified in the universal genetic code.

Amino acids can exist as both an acidic and a basic ion, known as the zwitterion. Compounds that can exist as both acid and base are known as amphoteric. Amino acids are found as the second largest component in the muscle but in the form of proteins.

Refer: Amino Acids – Properties, Functions, Sources and its Deficiency

What Are Proteins?

Proteins are macromolecules that are formed from residues of amino acids arranged in a chain. The proteins perform a vast array of functions such as DNA replication, catalysing metabolic reactions, transportation of molecules, providing structure to cells and responding to stimuli.

A simple linear chain of amino acids is called a polypeptide. A protein is made up of one or more chains of polypeptides. Short polypeptide chains with 20-30 amino acids are not considered proteins, they are simply referred to as peptides. Amino acids in a protein are held together by peptide bonds.

Refer: The Basics of Protein – Its Structure and Functions

Amino Acids vs Proteins

Amino Acids	Proteins
Definition
Amino acids are organic compounds that are made up of an amino group, a carboxylic group and a varying side chain.	Proteins are nitrogenous macromolecules that are made up of chains of amino acids.
Structure
It is the building block of proteins.	It is a string of amino acids.
Molecular Mass
Amino acids have a smaller molecular mass.	Proteins have a larger molecular mass.
Synthesis
All the 20 amino acids are not synthesised in our body.	All the proteins are synthesised in our body.
Composition
It is composed of an amino group, a carboxylic group and a varying side chain.	It is made up of amino acids joined together by peptide bonds.
Function
It is involved in the synthesis of proteins.	It functions to provide structure to cells, catalyses metabolic reactions and takes part in DNA replication.

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