Like each afternoon, Simon went out to play Seven Stones with his mates.
However, his friends made fun of his body, each time. He grew tired of it.
That day, he went back home crying to his mother. Shouting at her, he said, “Why am I short at this age, Mummy?”.
“This is due to the lack of protein in your body. However, yours is not a worse case there can be life-threatening conditions also”
Next morning in class, he asked his biology teacher about the importance of proteins. She said she will help.
Let us all find out about proteins
Berzelius coined the term protein in 1838. It is commonly understood as a long chain of amino acids.
Proteins are among the most important macromolecules of the cell.
They play a very significant role in the structure and metabolism of the cell.
Let us all discuss the Composition and Structure of Proteins
Proteins are composed of carbon, hydrogen, oxygen, nitrogen, and sometimes sulfur.
In addition, certain proteins contain phosphorus , iron, zinc, copper or iodine.
Let’s discuss Structural Subunit of proteins
Proteins consist of linear polymers of several types of alpha-amino acids, which are linked by peptide bonds.
These bonds are formed between the amino and carboxyl groups of successive amino acids.
Let’s talk about the molecular weight of the protein
The protein molecules are very large complex and have very high molecular weight.
The molecular weight of Adrenocorticotropin hormone is 4500, bovine insulin is 5,733 and bacterial ferredoxin is 6000. These proteins are amongst the proteins having minimum molecular weight.
The molecular weight of human hemoglobin is 66,500, enzyme urease is 483,000 and of enzyme pyruvate hydrogenase complex is 46,00,000.
Let’s discuss about the varieties of protein
Proteins are folded. Amino acids join one after the other to form polypeptide chains.
When a protein has only one polypeptide, it is called monomeric protein. For example Lysozyme.
And when the protein has two or more than polypeptides, it is known as oligomeric protein. For Example Insulin.
Proteins having more than 10 polypeptides is known as multimeric protein. For Example RuBisco
The proteins show unlimited variety because a polypeptide may have any number of 20 amino acids present in any proportion and arranged in any sequence.
Some reasons for variations are
Variation in the types of amino acids forming a polypeptide chain.
Variation in the length of polypeptide chains.
Innumerable combinations of amino acid sequences in polypeptide chain.
Example protein with 40 amino acids can have 20 to the power 40 varieties of polypeptide chains.
Variation in the number and types of polypeptide chains in a protein molecule.
Let's Recap.
Amino acids are building blocks of protein
Proteins are composed of carbon, hydrogen, oxygen, nitrogen and sometimes sulfur.
Proteins are linear polymers of several types of a-amino acids, which are linked by peptide bonds.
The protein molecules are very large complex and have very high molecular weight.
Proteins show many variations as there can be many possible combinations of amino acids arranged in a polypeptide chain.