The key difference between simple protein and conjugated protein is that simple proteins are made of amino acids bound together to form a large molecule, whereas conjugated proteins are complex molecules containing simple proteins and non-protein components.
A protein is a biopolymer molecule. That means; a protein molecule contains a number of repeating units bonded to covalent bonds. These repeating units represent the amino acids that were used in the formation of the protein. According to the chemical composition of proteins, there are two types of proteins as simple proteins and conjugated proteins.
CONTENTS
1. Overview and Key Difference
2. What is a Simple Protein
3. What is a Conjugated Protein
4. Side by Side Comparison – Simple Protein vs Conjugated Protein in Tabular Form
5. Summary
What is a Simple Protein?
Simple proteins are peptide chains having amino acids but no other non-protein components. Therefore, upon the hydrolysis of these proteins, simple proteins give only amino acids as the products. However, these proteins occasionally give trace amounts of carbohydrate components as well upon their hydrolysis. Some common examples of simple proteins include albumin, glutelins, albuminoids, histone proteins, and protamines. When considering the enzymes, there are simple proteins that can act as enzymes in the human body, including digestive enzymes such as trypsin, chymotrypsin, and elastase.
Figure 01: Digestion of Simple Proteins
What is a Conjugated Protein?
Conjugated proteins are peptide chains having both amino acids and non-protein components. Therefore, upon hydrolysis, these conjugated proteins give both amino acids and non-amino acid components as well. Here, the non-protein components are also bound to the protein via covalent bonds. The non-amino components in the protein are called the prosthetic groups. Most of these prosthetic groups form from vitamins. We can classify conjugated proteins based on the chemical nature of the prosthetic group. Some common examples for this type of proteins include lipoproteins (contains a lipid residue), glycoproteins (contains a sugar residue), phosphoproteins (contains a phosphate residue), hemoproteins (contain an iron residue), etc.
Figure 02: Hemoglobin
Hemoglobin is a type of conjugated proteins which has a heme group as the prosthetic group. This heme group contains a ferrous ion center which can transport oxygen in its dimolecular form via forming a coordinate bond between the ferrous ion and oxygen molecule. Therefore, this conjugate protein is very important in transporting molecular oxygen throughout our body through the bloodstream. Generally, glycoproteins are the largest and most abundant member of the group of conjugated proteins.
What is the Difference Between Simple Protein and Conjugated Protein?
There are two types of proteins depending on the chemical composition: simple proteins and conjugated proteins. The key difference between simple protein and conjugated protein is that simple proteins are made of amino acids bound together to form a large molecule, whereas conjugated proteins are complex molecules containing simple proteins and non-protein components. Albumin, glutelins, albuminoids, histone proteins, and protamines are simple proteins while lipoproteins, glycoproteins, phosphoproteins, and hemoproteins are conjugated proteins.
The following table summarizes the difference between simple protein and conjugated protein.
Summary – Simple Protein vs Conjugated Protein
There are two types of proteins depending on the chemical composition: simple proteins and conjugated proteins. The key difference between simple protein and conjugated protein is that simple proteins are made of amino acids bound together to form a large molecule, whereas conjugated proteins are complex molecules containing simple proteins and non-protein components.
Reference:
1. “Conjugated Protein.” Wikipedia, Wikimedia Foundation, 12 Oct. 2019, Available here.
2. “Simple Protein – an Overview .” ScienceDirect Topics, Elsevier B.V., Available here.
Image Courtesy:
1. “2428 Digestion of Proteins” By OpenStax College – Anatomy & Physiology, Connexions Web site, Jun 19, 2013. (CC BY 3.0) via Commons Wikimedia
2. “Hemoglobin” (Public Domain) via Commons Wikimedia