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What Is Amino Acid Biosynthesis?

Andrew Kirmayer
Andrew Kirmayer

Amino acid biosynthesis is the metabolic process of producing substances needed by most living things. Many compounds in the body that use energy, process fat, and make neurotransmitters are either formulated automatically or have to be acquired through food. Non-essential amino acids are synthesized independent of nutritional intake, while essential ones are food-based. Ten of each type are often distinguished, so 20 amino acids in all are used by biological organisms to function. All of them are typically derived through biosynthesis pathways, or sequences of producing a compound out of another.

The nonessential varieties are often synthesized out of carbon molecules with the same structure. One can change into another if needed by switching substances on the molecule called ketoacids. Eating foods with one amino acid, however, usually does not compensate for the lack of another that it can be made into. Tryptophan is an important compound that is typically gotten from food, and is sometimes derived from methionine, the intake of which does not usually compensate for the loss. If not enough tryptophan is in the body, muscles can be broken down to release it, which can cause health issues in the case of an unbalanced diet.

The structure of lysine, an essential amino acid.
The structure of lysine, an essential amino acid.

Nitrogen is also required for amino acid biosynthesis. Some organisms can produce it, while complex ones like humans must rely on biochemical processes to make the element. Biosynthetic reactions also rely on stereochemistry, because most amino acids are chiral molecules that can be structured as mirror images of one another. The process of amino acid biosynthesis is regulated by systems that enable regulation. High levels of a particular final compound typically inhibit enzymes from triggering chemical reactions that otherwise occur.

Barley, which contains amino acids.
Barley, which contains amino acids.

Excesses of an amino acid often bind to a regulatory site on an enzyme, so it is not as active. The enzyme can then be directed to assist with other processes. Extra amino acids typically break down, so adding more to one’s diet usually has no benefit to health; seeds in plants and egg yolk are the only things that store the excesses. Amino acid biosynthesis can produce neurotransmitters such as dopamine, which generally controls a normal range of movement.

Genetic diseases that affect amino acid biosynthesis can trigger mental retardation because of neurological damage. They can also result in an inability to process hemoglobin, which can lead to physical and psychological abnormalities. Metabolic diseases called porphyrias can also trigger these symptoms, and the more defective enzymes that are produced as a result, the worse a person’s condition may be.

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    • The structure of lysine, an essential amino acid.
      By: Bioreg images
      The structure of lysine, an essential amino acid.
    • Barley, which contains amino acids.
      By: schankz
      Barley, which contains amino acids.