Proteins

Erika Molnar
Jul 25, 2016
6 min read

Our body is made approximately of 60% - 70% of water and there are Fifty Thousand of different proteins inside us.

We need to consume proteins to make our own protein.

Why and How?

In our Digestive system we break down food we eat in component molecules and these are called Amino acids.

So, a protein is composed by amino acids

Like seen below:

Amino Acids molecules have a sort of chemical “hook” on each of them, so it can be attached on each end, so it can be attached to any other one to make the proteins we need. To understand it better, it looks like a train.

The code that determines the sequence of Amino Acids (their order) is the DNA.

There are 20 of them, these are obtaining from food and eleven of them are manufactured in our body. Eight of them are essential in the diet, but the others we can make from those eight, if necessary.

THE TWENTY AMINO ACIDS :

Each amino acid has its own distinct function that works with other amino acids to build proteins. The particular combined molecular structure of the amino acids in a protein determine how it works. Of the following amino Acids 9 are essential ( indicated by " human nutrition") and the remaining eleven ( indicated by "Manufactured" ) can be Manufactured in the body.

Alanine - Manufactured

Arginine - Human Nutrition

Aspartate - Manufactured

Asparagine - Manufactured

Cystine -Manufactured

Glutamic Acid - Manufactured

Glutamine - Manufactured

Glycine - Manufactured

Histidine - Human Nutrition

Isoleucine - Human Nutrition

Leucine - Human Nutrition

Lysine - Human Nutrition

Methionine - Human Nutrition

Phenylalanine - Human Nutrition

Proline - Manufactured

Serine - Manufactured

Threonine - Human Nutrition

Tyrosine - Human Nutrition

Valine - Human Nutrition

Diseases and conditions in which one or more Amino Acids is deficient :

The following diseases and conditions indicate amino acid deficiency:

Children do not grow normally if they lack Taurine, argemine and cysteine. Older children and adults can make cysteine from amino acid methionine.

Amino acids from what we eat are not broken down in digestion or the small bowel into smaller units. They are absorbed directly through the bowel wall into the blood stream. Vitamin B6 helps form some Amino Acids and converts others to energy.

Adults who lack protein may feel dizzy and nauseated. Their skin becomes dry and scaly, they fatigue easily, and they become short-tempered. Infections, Kidney problems, and diarrhea become increasingly worse. Since protein is the main source of sulfur intake.

When protein is needed?

Protein is needed when we are too thin for our height and bone structure, or when we are depressed and lacking in get-up- and- go. Loss of vigor and stamina may be signs of deficiency.

Foods High in Protein?

The following foods are likely to supply the body with sufficient protein when used in the proper portion. The best sources are eggs, Fish , poultry and legumes. The recommended daily allowance ( RDA) for protein is 56 grams for adults males and 44 grams for adult females. Always eat at least 3 vegetable with every meal.

Activity :

In this activity you are provided with eight foods that contain protein. Can you work out which has the most protein? Take a paper and a pencil and arrange the foods in order from that containing the most protein at the top, to the least protein at the bottom.

(The answers will be in the end of the the following blog post so keep reading and leave your answers on a site for the moment. )

Do all foods high in protein build muscle?? Yes. The reason most bodybuilders focus on supplementing with arginine, glutamine, and ornithine is because they believe these three amino acids accelerate muscle building. (Ornithine is formed when an enzyme breaks down arginine) . Protein foods provide too much stimulation for some people and not enough in others. If a patient has too much protein, digestive problems result and there is an increased risk of Obesity , Kidney disease and cancer. More is not better in the case of protein , fats , or sugar.

Proteins are an essential component of our muscles and other structures in our body, such as hair, nails and tendons. As well as these structural proteins, there are proteins found in our blood that function as hormones, and others that form part of our immune system, which protects us against infection. The proteins in the food that we eat are digested by enzymes that are themselves proteins.

The excess amino acids in our diet cannot be stored for long in the body, if they are not needed for building new proteins. They are taken in the blood stream to the liver, where they are broken down. The part of the amino acid that contains the nitrogen is converted into urea, which circulates in the blood to the kidneys, which provide an amazing biological filtering system. They filter out the urea and send it down tubes to the bladder, along with other substances not needed by the body, and excess water, forming urine. So, when you wee, you are getting rid of surplus amino acids.

Protein sequence

Finding out the order of amino acids in a protein – called protein sequencing – was a major goal of biologists for many years.

The first one to be completed was insulin, a hormone secreted by the pancreas and involved in the regulation of glucose in the blood. Glucose is a sugar that the body uses for energy. Insulin is the hormone that is in short supply in people with Type 1 diabetes and is not functioning as it should in people with Type 2.

Although insulin is composed of only 51 amino acids, it nevertheless took almost six years for a group of research scientists in Cambridge to complete the task. The group was headed by Frederick Sanger, who was awarded the Nobel Prize for this work in 1958. Insulin turned out to be composed of two linked chains of amino acids, as shown above. Each amino acid is identified by a three letter abbreviation of its name.

Since then, protein sequencing has now become automated and, as a result, the time for the process can now be measured in hours, rather than years.

Phenylketonuria

One of the common amino acids in our diet is phenylalanine (pronounced as fee – nile – alla – neen). Its abbreviation is Phe. Have a look at the structure of the insulin protein above and see how often phenylalanine occurs in it.

Phenylalanine is found in many high protein foods like meat, fish, eggs, cheese and milk. However, there is a rare genetic defect, phenylketonuria (PKU), present from birth, which makes some people unable to break down this amino acid. In people with this condition, the extra phenylalanine that they take in that is not needed to be made into their own proteins, builds up in their blood and other tissues. If undetected, it damages the brain and nervous system, and is likely to lead to learning disabilities and other problems, probably requiring lifelong care. However, if the PKU is detected early enough, the person can be put onto a low protein diet, with amino acid supplements that ensure enough of the other amino acids, and they should then remain perfectly well.

‘Early enough’ means very early in life! All babies in the UK and most other developed countries are routinely screened for phenylalanine level by means of the heel prick test, which is carried out within the first week of a baby’s life. Other rare but serious conditions are also tested for using the same drop of blood. If PKU is detected, the baby will be put onto a special low protein formula milk, with supplementary amino acids, and the child will need to continue on a low protein diet. As an adult, they may be able to resume a normal or near normal diet, or they may need to maintain a low protein diet throughout life.

Answer - Activity

You may be surprised to find the egg, which are often considered to be a good source of protein come a long way down the list. An egg contains only 21% protein compared with over 30% in chicken and steak. That is because the eggs contain a lot more water than meat, which is also why the inside of a raw egg is quite runny.

When a egg is hard- Boiled, although is appears dry, it has not lost any of the water. In the uncooked egg, the microscopic protein molecules( made up of chains of amino acids) are curled up into neat balls. The water molecules lie between them , allowing them to roll over one another, so that the egg is runny. When the egg is cooked , the heat causes the neat little balls to unravel and the protein molecules then form bridges across from one to another , similar to the ones shown between the 2 chains of insulin in protein sequencing. This makes the egg solid. The water molecules are still present, but trapped in the network of the protein molecules.