Amino acids are organic compounds that are part of all tissues of the human body. They are responsible for metabolic processes and energy metabolism, ensuring the functioning of the body. Amino acids directly affect the state of the nervous system, regulating mental activity, mood and sleep.

These components are necessary for the formation of muscles, tendons and ligaments, as well as hair and skin. Without a sufficient amount of amino acids, active growth of muscle mass is impossible. In sports and fitness, amino acids increase the performance of an athlete and accelerate the process of building muscle mass. They help you recover faster after hard workouts and relieve muscle pain.

Beneficial properties of amino acids [1, p. 14]:

• creation of new cells;
• tissue regeneration;
• immune support;
• increase in muscle mass;
• normal course of metabolic processes;
• getting rid of excess weight;
• strengthening the nervous system and increasing concentration;
• providing the body with additional energy;
• improvement of the condition of skin, nails, hair.

Amino acids have antioxidant properties. These substances significantly slow down the aging process, keeping the skin young and elastic. They also stimulate sexual desire and increase libido.

All amino acids are divided into essential and non-essential. There are also partially replaceable substances that are synthesized in the human body in insufficient quantities. They can only be produced under certain conditions or during a certain age period.

Partially replaceable substances include cysteine, histidine, tyrosine, and arginine, which is not produced in children and adolescents. Sources of partially essential amino acids include lean meats, soybeans, peanuts, pumpkin seeds, cheese and lentils[2].

For proper functioning, the body uses 22 amino acids, of which 10 substances are synthesized independently. The remaining 9 components must be obtained from food or dietary supplements. The diet should also contain foods rich in partially essential amino acids[2].

Essential amino acids (BCAAs) are substances that are not produced by the human body. They can only come from food or synthetic food additives.

The category of essential amino acids includes 9 substances[3]:

• valine – a stimulant important for muscle metabolism and recovery after training;
• histidine is part of hemoglobin, stimulates tissue growth and repair;
• leucine – characterized by an anabolic effect, protects muscle tissue, and is also effective in the treatment of arthritis;
• isoleucine – promotes the formation of hemoglobin, accelerates muscle growth, helps cells absorb glucose;
• threonine – responsible for the balance of protein compounds in the body;
• methionine is a hepatoprotector and has a metabolic effect;
• lysine – has bactericidal properties, strengthens the immune system;
• tryptophan – an immunoprotector, participates in the synthesis of the hormone of happiness – serotonin;
• Phenylalanine is an important component used in the treatment of many diseases (vitiligo, ADHD, depressive disorders).

Nonessential amino acids include substances that are synthesized by the body itself. They are mainly produced in the liver.

List of essential amino acids[3]:

• asparagine – is involved in the production of ammonia and is necessary for the normal functioning of the nervous system;
• alanine – part of proteins and biologically active substances;
• proline – is an integral part of the collagen protein;
• glycine – part of biologically active compounds, acts as a receptor in the brain and spinal cord;
• carnitine – participates in the transport of fatty acids;
• taurine – plays an important role in lipid metabolism, accelerates wound healing;
• serine – a building material for creatine, is involved in the transformation of glycogen;
• ornithine – has anti-catabolic properties, used in sports medicine;
• glutamine – ensures muscle growth and strong immunity;
• glutamic acid – acts as a receptor.

Amino acids are necessary for athletes and ordinary people. These substances perform many important functions in the human body. Amino acids help you lose weight because they regulate metabolism and ensure the proper functioning of the digestive system.

The importance of amino acids for athletes cannot be overstated. With a lack of amino acids, it is difficult to imagine gaining muscle mass, effective training process and recovery from injuries.

Amino acids are found in most traditional foods and are also available as dietary supplements. The substances are safe to use and do not cause addiction or negative side effects.

Enzymes play a key role in metabolism – complex protein molecules that act as biological catalysts. They accelerate the rate of chemical reactions occurring in the body millions of times. Without enzymes, these reactions would proceed too slowly to support life.

Each enzyme has specificity, meaning it is able to bind and speed up only a specific chemical reaction. This specificity is provided by the unique structure of the enzyme, which has a site ideally suited to bind the substrate molecule involved in the reaction. After the enzyme binds to the substrate, an enzyme-substrate complex is formed, in which the chemical transformation of the substrate into the reaction product occurs. The product is then released, leaving the enzyme unchanged and ready to bind to a new substrate molecule.

There are many different enzymes, each with its own specific function in metabolism. For example:

• Amylase – breaks down carbohydrates in food into glucose, the main source of energy for cells.

• Pepsin – breaks down proteins in the stomach into smaller peptides.

• Lipase – breaks down fats in the intestines into fatty acids and glycerol.

• Lactate dehydrogenase – plays an important role in the process of obtaining energy from glucose.

Lack of or impaired activity of certain enzymes can lead to various diseases. For example, lactase deficiency leads to intolerance to lactose, milk sugar. In this condition, the body is unable to break down lactose from milk, causing symptoms such as bloating, diarrhea and pain.

To maintain health, it is important to provide the body with all the necessary nutrients that serve as cofactors for enzymes. Cofactors are inorganic molecules or vitamins that enzymes need to function properly. For example, vitamin B1 (thiamine) is a cofactor for many enzymes involved in energy metabolism.

Enzyme activity is an important aspect of metabolism that the body must carefully monitor. There are several ways to regulate enzyme activity, allowing cells to adapt to different conditions and needs:

• Substrate concentration: When the concentration of a substrate in a cell increases, the likelihood of it binding to the enzyme increases, resulting in a faster reaction. On the contrary, when the substrate concentration decreases, the enzyme activity decreases.

• Enzyme inhibition: Inhibitors are molecules that bind to an enzyme and block its active site, preventing it from binding to its substrate. There are different types of inhibitors, some of which bind to the enzyme irreversibly, while others bind reversibly. Inhibition allows cells to regulate enzyme activity depending on needs. For example, hormones can act as inhibitors by regulating the activity of enzymes involved in metabolic pathways.

• Enzyme modification: Some enzymes can undergo modification, such as phosphorylation, which changes their structure and affects their activity. Phosphorylation can activate or deactivate the enzyme depending on the specific modification.

• Induction and repression of enzyme synthesis: Cells can regulate enzyme activity at the level of gene expression. Induction is a process in which certain molecules stimulate the synthesis of an enzyme. Repression, on the contrary, blocks the synthesis of an enzyme when the cell does not need it. In this way, cells can control the total amount of enzymes available for a reaction.

Understanding the regulation of enzyme activity is of great importance for medicine. Many drugs act by inhibiting enzymes involved in pathological processes. By studying the regulation of enzymes, scientists can develop new effective drugs to treat various diseases.

Enzyme research is constantly evolving. Scientists are developing new genetic engineering methods to create enzymes with improved properties. For example, it is possible to create enzymes that work at higher temperatures or in more aggressive environments. These enzymes can be used in various industrial processes such as bioproduction or wastewater treatment.

In addition, studying enzymes can help develop new treatments for diseases. For example, scientists are exploring the possibility of using enzyme therapy to treat genetic diseases caused by mutations in genes that code for enzymes.

In conclusion, enzymes are essential molecules that play a vital role in human metabolism. They speed up the chemical reactions needed to produce energy and build and maintain body tissue. Understanding the role of enzymes allows us to become more aware of the importance of a healthy diet and maintaining balanced levels of vitamins and minerals for optimal body function.