Proteins in human body: formation, roles, and uses
About 16% of the human body is made up of protein. Protein is one of the essential components in the human body which makes the maximum of our muscle mass. Protein is one of the macronutrients which provide energy for body functioning. Protein is basically needed for the overall growth of the body. So, now let’s understand how is it produced in our body.
Amino acids are the building block of protein. These amino acids are linked together by peptide bonds forming a long chain. These peptide bonds are formed by dehydration synthesis reaction between carboxyl groups of two amino acids. When we come across the central dogma of molecular biology, we get to know that the information in our DNA (deoxyribonucleic acid) is transcripted into RNA (ribonucleic acid) by a process known as Transcription. That information on RNA is finally translated into Protein by the process of Translation. So, let us know in details what are these processes all about.
If we don’t understand a script suppose Devanagari, we try to decode it into our mother-tongue. Same way, the code present on our DNA is high level and is thus transcripted into mRNA which is handy. Transcription in prokaryotes takes place in three simple steps:
1. Initiation- The process involves an enzyme known as RNA Polymerase. The region where RNA polymerase binds with DNA is known as Promoter and this is the place where initiation begins. During initiation, RNA polymerase comes and bind to DNA, forming a closed complex. Enzymes help in the local unwinding of DNA, and RNA synthesis begins. When mRNA is eight to nine base pair long, the core enzyme carries forward the elongation process.
2. Elongation- After initiation comes elongation. In this process, local unwinding shifts, elongating the mRNA until it reaches the termination site.
3. Termination- Termination in eukaryotes consists of the formation of a polyadenine chain. Termination in eukaryotes is not dependent on a specific protein called rho protein and is therefore called Rho-independent termination. Those sequence binds to each other forming a hairpin loop structure. In the end, the uracil sequence present in mRNA detaches itself from DNA containing Adenine sequence and mRNA gets free.
After these steps, there is a post-transcriptional modification which includes the addition of 7-methyl guanosine cap, the addition of polyadenine tail, and splicing out of introns (the non-essential part).
The decoder of our cells needs to translate the language from our messenger RNA to the language of the synthesiser so that it can form a protein. There are certain sequences on mRNA read in triplets and are known as triplet codons. These codons codes for different amino acids. Amino acids then undergo dehydration synthesis reaction between carboxyl groups of two different amino acids. Translation also includes the steps of initiation, elongation, and termination which is different from that of transcription. Then there is some post-translational modification after which our required protein is generated.
Food rich in protein:
Food that contains the maximum amount of protein is meat, eggs, fish, nuts, legumes, dairy products like milk, cheese, yoghurt, etc.
Roles of protein in the human body:
1. To build-up muscle mass.
2. To repair any tissue damage.
3. Synthesis of certain enzymes, and chemicals in the body.
4. To build-up bones, cartilages, blood, etc.
5. Promotion of biochemical reactions such as digestion.
6. For over-all body growth.
7. To balance body fluids.
So, now that you know how important protein is to your body, I hope you will try to intake the permissible amount per day and help your body grow.