Probably no secret that aminocarboxylic acids (amino acids) are beads in the complex chain of proteins of any living organism. But few people know that almost all of them were discovered in the second half of the last century.
The biogenic sulfur-containing amino acids of interest to us in this article are cysteine and methionine. Let's try to enrich the reader's knowledge of these two organic compounds from the point of view of biochemistry and biology of our he alth.
The building blocks of protein
Amino acids (including sulfur-containing ones) are organic compounds quite widely represented in nature. Today we know more than 500 amino acids. At the same time, 240 of them are found in the environment in a free form, and all the rest are intermediate products of metabolic processes in living organisms.
And today remainsa mystery why of all this diversity only 20 amino acids are found in human proteins (pictured above). They are called biogenic, or involved in protein biosynthesis. Among these "selected" only two are sulfur-containing amino acids. These are methionine (Methionine) and cysteine (Cysteine), which contain a sulfur atom.
All amino acids for our body are divided into two groups: essential (those that are not synthesized in the human body) and nonessential (those that the body can produce itself). Cysteine belongs to the second group, but methionine - to the first, which we must receive with food - it is with it that the pathologies are associated, which are caused by a violation of the metabolism of sulfur-containing amino acids. But first things first.
What is C5H11NO2S?
Methionine in its pure form is colorless crystals, rather unpleasant smelling and soluble in water. This is an amino acid that serves as a supplier of methyl groups and sulfur in our body. As already mentioned, methionine is an essential sulfur-containing amino acid and is not synthesized in the body.
It comes from food and is used by our cells to assemble their own proteins on ribosomes. This sulfur-containing amino acid is found in milk protein (casein), eggs, sesame, flour, pork and chicken, fish (salmon and tuna), wheat and oats, legumes, all green vegetables, parmesan cheese and mozzarella.
In addition, modern pharmacology has in its arsenal drugs that are absolutely identical to methionine. Thanks to himrole in protein synthesis and fat soluble properties these products are widely used in the sports field.
The value of methionine for the body
The biochemistry of the exchange of sulfur-containing amino acids supplies our body with sulfur and methyl groups. This amino acid plays a significant role in the synthesis of cysteine, taurine, adrenaline and melatonin.
Its functions in the body are varied and quite wide:
- Participates in lowering cholesterol levels and helps prevent atherosclerosis.
- Acts as a hepatoprotector - protects the liver from the deposition of excess fat, restores its structure.
- Good for kidneys and excretory system.
- Acts as an antidepressant, restores and normalizes sleep, eliminates chronic fatigue.
- Improves the condition of skin, nails and hair.
- Able to neutralize toxic metals, free radicals and thus ensure intoxication of the body.
- Improves the condition of the joints. It has been proven that in patients with arthritis, the amount of sulfur in the cartilage is reduced by 3 times compared to the norm.
And this is not a complete list. It is believed that in order to provide our body with this amino acid, it is necessary to receive 19 mg of methionine per 1 kilogram of weight per day.
C3H7NO2S - protector and cleaner
Cysteine is an amino acid that is synthesized in our body from methionine. This process is multi-stage and occurs in the presence of specific enzymes, vitamins. It may failoccur at each stage, and this is also associated with pathologies of the exchange of sulfur-containing acids.
Derivatives of the breakdown of cysteine are taurine and glutathione. The first is a protein that is responsible for the adequate functioning of the brain, and the second plays an important role in the functioning of the immune system. Cysteine itself affects the condition of the skin (responsible for collagen synthesis) and detoxification processes. It is also part of many digestive tract enzymes.
Value for the body
It should be noted such positive functions of this amino acid:
- Cysteine improves hair growth by providing collagen synthesis, which has a positive effect on skin formation and nail structure.
- This sulfur-containing amino acid helps build muscle and burn fat.
- Performs the function of an antioxidant, removing toxins, especially when taking vitamin C and selenium at the same time.
- Activates leukocytes and lymphocytes, affecting their antiviral, antitumor, anti-inflammatory properties.
The daily requirement of cysteine for a he althy adult is up to 3 grams per day. At the same time, increasing the dose can lead to toxic poisoning.
Beautiful color reaction
Determining the presence of methionine and cysteine is easy, and this experience is often shown in high school. The reaction to sulfur-containing amino acids (Fol reaction) is one of the few nominal, beautiful and spectacular chemical transformations.
It's done like this. In a test tube containing lead acetate (1 ml), add 10% sodium hydroxide solution and chicken protein. Thenthe mixture is heated. A black precipitate appears in the test tube, and the darker it is, the more sulfur-containing amino acids are present in the solution.
The reaction is based on the splitting of sulfur with alkali to form hydrogen sulfide, which binds with sodium and precipitates.
The reaction is widely used in clinical and biological research, pharmaceuticals.
Scarce conditions
Homocystinuria is a hereditary pathology of the metabolism of sulfur-containing amino acids. It affects the nervous, musculoskeletal, vascular systems, accompanied by mental retardation, convulsions, pathologies of the lens of the eye and optic nerves, disorders in the formation of the skeleton and muscles.
The frequency of pathology is 1 case per 100 thousand newborns. In the case of early diagnosis of this type of enzymopathy, treatment includes a diet with the exception of methionine and vitamin therapy.
This is not the only pathology of the metabolism of sulfur-containing amino acids, but the others are even rarer.
Acquired impairments
Deficit conditions usually manifest themselves in the form of brittle nails, hair loss, swelling of soft tissues, exacerbations of diseases of the heart, liver and kidneys.
For people with high stomach acidity, taking methionine-rich foods is practically contraindicated. Its excess in the body causes allergies, drowsiness and digestive disorders.
But under stress and physical exertion, our body requires an increase in sulfur-containing amino acids indiet. In addition, pregnant women should not neglect foods rich in them. This is the key to the normal formation of the nervous system in the fetus.
Slimming Helper
In the top five amino acids that will help you lose weight, cysteine is not the last one.
This amino acid signals to the brain that the stomach is already full. Thanks to cysteine, we feel full. And this leads to the prevention of overeating, weight loss and an increase in the rate of weight loss.
Eat broccoli, oatmeal with bananas, eggs, sea fish - and this anorexigenic amino acid will help you achieve a slim figure.
