Classification of proteins

Types of proteins
Proteins are the most abundant macromolecules within the cell. Each of them has a specific function, but not all are equal, so they have a classification, which determines the various types of proteins. This classification is useful to relate them to the function they fulfill.


What are proteins?

If you still do not know, I’ll tell you that the proteins are macromolecules that are colloidal, represent more than 50% of the dry weight of the cell. They are composed of amino acids, there are 20 different amino acids that are linked together by polypeptide bonds.

For a better understanding of what proteins are, what their properties are , how they act, the types of proteins and their functions, they are classified in different ways: taking into account their chemical composition, structure, functions and solubility in different solvents.

Knowing what the different types of proteins are and how they are classified can be very helpful in understanding which functions fulfill the different proteins within your body that allow you to stay healthy. Would you like to meet them? Take note of the following paragraphs.

Classification of proteins

By its chemical composition

  • Simple proteins . They are those that when they hydrolyze (to degrade) only produce amino acids.
  • Complex proteins . They are those that when hydrolyzing, produce amino acids and other organic and inorganic compounds. These may be: metal proteins, nucleoproteins and phosphoproteins.

Next we will see the different groups in which the simple proteins are classified.

  • Albumin : These proteins are soluble in water, found in all cells of the body and also in the bloodstream. Examples of albumins are lactobumin found in milk and serum albumin found in the blood.
  • Globulins : These proteins are insoluble in water but are soluble in dilute salt solutions with strong acids and bases. Examples of globulins are milk lactoglobulin and ovoglobulin.
  • Glutelins : These proteins are soluble in dilute acids and in alkalis. Wheat glutelin protein is a good example of glutelins. These are only produced in plant material.
  • Prolamines : These proteins are soluble in 70 or 80% alcohol. Among them we can highlight the fliadin of wheat and the zein of maize. They are found only in plant materials.
  • Albumunoid : Albuminoids or selenoproteins are insoluble in all neutral solvents, dilute alkalis and acids. They are found in connective tissues, hair and nails. Some examples are keratin, which is found in the keratinized layers of the skin and in the cortex or cortex of hair and nails and the collagen found in the white fibers of the areolar tissue.
  • Histones : These are water soluble proteins in which the basic amino acids are predominant. They are rich in arginine or lysine. DNA eukaryotes of chromosomes are associated with histones in the formation of nucleoproteins.
  • Protamines : These proteins are soluble in water and in basic low molecular weight polypeptides (about 4000 daltons). They are very rich in arginine amino acids. The polypeptide chain consists of 28 amino acid residues, including 19 arginines and 8 or 9 non-basic amino acids. Protamines are linked to the DNA of the spermatozoa of some fish. Examples of protamines are salmin (salmon) and sturin (sturgeon).

We will now look at the types of complex proteins.

  • Nucleoproteins : (Protein + nucleic acid). Nucleoproteins are proteins combined with nucleic acids. In trout, nucleoproteins of sperm constitute 90% of the solid material and in erythrocyte nuclei, almost 100% of nucleoproteins are combinations of nucleic acids with simple basic protein protamines. Nuclehistones are combinations of nucleic acids with the basic protein of simple histone. Additionally, several acidic proteins, non-histone proteins.
  • Glycoproteins(Proteins + carbohydrates): Glycoproteins are proteins combined with carbohydrates. In most glycoproteins, binding is done between asparagins (ANS) and N-acetyl-D-glucosamine (GIcNAc). The salivary glands and mucous glands of the digestive tract secrete mucoproteins in which N-acetylglucosamine and serinel threonine of the protein are combined. Glycoproteins are divided into two major categories, intracellular and secretory. Intracellular glycoproteins are present in cell membranes and play an important role in the interaction and recognition of the membrane. Some examples of secretory glycoproteins are: plasma glycoproteins, liver segregations, thyroglobulin, thyroid gland secretions, immunoglobulins, plasma cell segregations,
  • Phosphoproteins (protein + phosphate): Phosphoproteins are proteins combined with a phosphate-containing radical, other than a nucleic acid or a phospholipid acid. Examples of phosphoproteins are milk casein and ovovitellin from eggs.
  • Chromoproteins : These are the proteins, combined with a prosthetic group, that is, a pigment. Examples of chromoproteins are the hemoglobin and haemocyanin, visual purple or rhodopsin respiratory pigments found in the eye canes, flavoproteins, and cytochromes.
  • Lipoproteins : These are lipid-conjugated proteins. There are four types of lipoproteins, high density lipoproteins (HDL) or a-lipoproteins, low density lipoproteins (VLDL) or pre-? lipoproteins and chylomicrons.
  • Metaloproteins : These are proteins conjugated with metal ions that are not part of the prosthetic group. These include ceruloplasmin, an enzyme with oxidase activity that can transport copper in the plasma and siderofilin found in iron.

By its conformation

According to their form, proteins can be divided into two types:

1.- Fibrous proteins . They are those that are formed by polypeptide bonds, forming compact structures called fibers. For example:

  • Fibroin . It is produced by insects, especially by spiders and silkworms.
  • The collagen . It is the major protein component of connective tissue.
  • Keratin . You can find it on the nails, claws, beaks, nails, horns, hair, wool and the outer layer of your skin.
  • Elastin . Provides elasticity to your skin and blood vessels.

2.- Globular proteins . They are formed by polypeptide bonds that adopt a spherical shape. For example: enzymes, antibodies, hormones. Most of the proteins you know belong to this type. They perform structural and mechanical functions, acting as:

  • Enzymes
  • Hormones . Many of these components are proteins, capable of regulating many cellular functions, related to metabolism and reproduction. Examples are insulin, glucagon and thyroxine.
  • Transporter proteins and membrane receptors . For example, hemoglobin.
  • Proteins carrying triglycerides, fatty acids and oxygen in the blood . They are responsible, among other functions of the contraction of muscle fibers.
  • Immunoglobulins or antibodies . They are glycoproteins that recognize antigens expressed on the surface of viruses, bacteria and other infectious agents.
  • Proteins of reserve . Examples of proteins of this type of protein are ferritin, which stores iron inside cells, and milk casein, which acts as a buffer of amino acids.

By its solubility

This way of classifying proteins takes into account their solubility in different solvents such as water, salt and alcohol . But, you may be wondering: where can I find protein to keep my body healthy? Pay attention to the following list.

Foods with proteins

Sources of animal origin

  • Beef
  • Pork
  • Milk
  • Fish
  • eggs
  • Cheese
  • Yogurt
  • butter
  • eggs

Sources of plant origin

  • Soy
  • Bean
  • Vegetables
  • Wheat germ
  • Quinoa
  • Almonds
  • Hazelnuts
  • Walnuts
  • Peanut
  • Peanut butter
  • Sunflower seeds
  • Walnuts
  • Tofu
  • Tempeh

Protein intake: recommended dose

Remember that the amount of protein you need in your daily diet will depend on the calorie needs required by your body . These vary according to the physical activity you perform. The recommended daily intake of protein for an adult comprises 10% to 35% of the total calorie requirement .

For example, if you maintain a 2,000 calorie diet you will need to consume 100 g of protein so that it gives you 20% of the total daily calories your body needs.

Healthy Recipes Rich in Protein

So that you do not fall into the routine of always preparing the same dishes when it comes to consuming proteins, I recommend you take a look at the recipes that make up the following list, sure you will love it!

  • Protein Shake . You will discover how to prepare this drink that combines perfectly flavor and an extraordinary nutritional content, mainly in proteins.
  • Peruvian ceviche recipe . You will know all the secrets that will allow you to prepare this delicious and healthy traditional recipe of Peruvian cuisine.
  • Fideau of meat . You will find a simple recipe to prepare this delicious and nutritious protein dish, which will bring the necessary nutrients to your body to stay healthy.
  • Greek yogurt recipe . You will know all the tips and secrets to prepare this delicious and healthy source of proteins, which will give you an extra energy to start your day with a lot of vitality and optimism.


Food Fiber: Types of Fiber, Properties and Benefits

Collagen and Keratin: Hair Benefits