Protein Classification

Protein Classification

In order to make a protein classification, we need to know what they are made up of first

Proteins are macromolecules made up of a series of amino acids that are bound together by peptide bonds. Moreover, they are involved in each and every single one of the processes carried out by the metabolism.

In general, we take them from the diet and the body breaks them down in the stomach in order to synthesize its own proteins.

Before jumping into the protein classification, we want to mention some concepts

1. Amino acid types

This article is going to focus on the different types of proteins that exist.

Before we continue, it is indispensable to mention two types of amino acids in order to understand their structure properly.

These are the ones:

  • Essential amino acids. These are all those amino acids that our body cannot produce. Therefore, it is necessary to obtain them from the diet.
  • Non-essential amino aids. These are the ones that the body can synthesize from the essential ones.

2. Origin of Proteins

It is possible to make a differentiation between the proteins that come either from animals or plants.

In fact, the quality and intrinsic features of each type are quite different…

This would be the first criteria for protein classification:

Animal Protein

Evidently, animals have a genetic code that is much similar to ours than that of plants. Consequently, the amount of amino acids from their proteins is quite similar to ours.

That is why they have a high biological value

In fact, animal meat has all the amino acids our body needs and just in the right amounts.

Vegetable Protein

Vegetables are also excellent sources of amino acids. However, the problem is that they do not have all of them or the right amounts.

Therefore, we would need to combine several types of vegetables in order to obtain all the amino acids that we need.

For example, a meal that is made up of a 75% of cereals and a 25% of legumes will provide all the proteins our body needs

3. Simple and Complex proteins

Once we understand the differences between the proteins from different foods, it is time to talk about their composition.

Therefore, another way to make a protein classification would be to talk about two big groups, which are:

Simple proteins

These are the ones that are only made up of amino acids or derivatives.

Moreover, they produce unique amino acids when they are hydrolyzed by enzymes, acids or alkalis.

For instance, some of them would be albumins, globulins or prolamines

Complex proteins

To put it simply, we use this term to talk about all those simple proteins that have a non-protein element within their structure.

There are known as protein groups

Depending on the type of prosthetic group, we can classify them as:
  • Nucleoproteins (protein plus nucleic acid).
  • Glycoproteins (protein plus carbohydrates).
  • Phosphoproteins (protein plus phosphate).
  • Chromoproteins (protein plus chromatic pigment).
  • Lipoproteins (protein plus lipid).
  • Metalloproteins (protein plus metal ion).

Protein molecules

4. Types of protein according to their organic function

As we previously mentioned, the proteins that we take from the diet have to be broken down and metabolized. Therefore, our body will be able to produce different proteins that will help us perform many functions.

In fact, this process involves breaking down peptide bonds and separating the amino acids to produce completely different proteins.

Therefore, we can distinguish up to 8 types for this protein classification:

Structural proteins

These are indispensable for all the tissues from our body, which is why they are structural proteins.

Inside this group, we can also find:

  • Collagen, which is in charge supporting the connective tissue from the cartilage, skin, tendons, bones and muscles.
  • Keratin, which is part of the nails, teeth and hair.
  • Elastin, a macromolecule that provides flexibility and elasticity to the tissues and organs.

Hormonal proteins

To put it simply, hormones are protein released by the cells that make up the endocrine hormones.

Its main function is to send signals between the different cells that make up the organism. That is why they constantly travel through the bloodstream which is why they are also called “chemical messengers”.

A good example of a hormonal protein is insulin, a substance released by the pancreas. Above all, its purpose is to regulate the blood sugar levels

Enzymatic proteins

Enzymes are in charge of supporting the reactions that take place inside the cells, that is why they are also known as catalysts.

In general, these proteins are in charge of transforming glycogen and glucose. Moreover, they play an indispensable hepatic and digestive functions apart from supporting the blood coagulation.

In fact, they are in charge of breaking down the food in order to obtain basic units that will help us absorb the basic nutrients for life

Defense proteins

Did you know that antibodies are essentially proteins?

Moreover, immunoglobulins are also made up of these type of macromolecules.

Therefore, they are in charge of protecting the organism against viruses, bacteria, fungi and, in general, all the microorganisms that could threaten our health and well-being.

Transport proteins

Without this type of proteins, the nutrients obtained during the digestion would not be able to reach the cells.

But they also transport many other types of substances and elements

For example, hemoglobin carries the oxygen from the lungs to each and every single one of the tissues so that they can function properly.

Then, myoglobin absorbs this oxygen and gives it to the muscle. In addition, albumin is in charge of transporting fat through the bloodstream.

Storage proteins

Our organism is always ready for periods of scarcity. That is why it always stores all kinds of substances in order to be able to deal with a potential deficiency.

This process is carried out by storage proteins, which are the ones in charge of storing some minerals. For example, iron, an indispensable mineral for the formation of hemoglobin.

This specific protein is called ferritin and it is also in charge of regulating the blood iron levels and countering the negative effects of an excess

Contractile proteins

The two main ones are actin and myosin, which are present in all the muscle tissues that make up the organism.

In fact, its main function is to regulate the contraction strength and speed

For instance, in order to illustrate their importance, they are the ones in charge of contracting and relaxing the heart

Receptor proteins

Have you ever wondered why are you thirsty or why you feel like eating a specific food?

Well, these reactions are due to receptor proteins. Their main function is to control the substances that enter and come out of all the cells. For example, minerals, water and all nutrients in general.

That is why, in case of detecting a deficiency of a substance, they will stimulate the endocrine glands in order to release hormones such as insulin, epinephrine or the digestive enzymes.


Perhaps, before reading this article, you may have though that proteins were only used to create muscle tissue.

In fact, if you are an athlete you probably take protein supplements in order to gain muscle and have bigger and more defined muscles. But you are also getting all the energy you need in order to perform vital processes.

Protein sources

That is why you should also take care of your diet and balance the intake of animal and vegetable products

We hope that this article was helpful and that you will be able to distinguish the main types of protein and their functions

Related Entries

Protein Classification Review

Simple and Complex - 100%

Organic Function - 100%

Defense Proteins - 100%

Conclusions - 99%


HSN Evaluation: No Ratings Yet !
Content Protection by
About Melanie Ramos
Melanie Ramos
Melanie Ramos uses the HSN Blog to share the latest information and content, so that all those readers who want to learn.
Check Also
Native protein
Native Whey – Characteristics and Differences from Normal Whey

Nowadays it’s very common for active and sporty people to be concerned about both their …

Leave a Reply

Your email address will not be published. Required fields are marked *