Asparagine

Asparagine, also known as L-aspartate, is a non-essential amino acid found in many plant and animal foods. It was first isolated from asparagus in 1806, hence its name. Asparagine plays a central role in cellular metabolism and is important for protein synthesis as well as the function of the nervous system. It is also an important building block for the biosynthesis of other amino acids.

What are the benefits of asparagine?

Studies in humans and animals have shown that asparagine can fulfill various vital functions in the body:

  • Protein synthesis: Asparagine is required for the synthesis of proteins, which are essential for growth and repair processes in cells. It serves as a transport molecule for nitrogen, thereby supporting the build-up of proteins and other amino acids (1).
  • Nervous system: This amino acid is important for the central nervous system, particularly for the regulation and transmission of nerve impulses. It contributes to the production of neurotransmitters, which are needed for communication between nerve cells (2).
  • Detoxification: Asparagine plays a role in the urea cycle, through which excess nitrogen is converted into a non-toxic form and excreted in the urine. This helps detoxify the body of harmful metabolic byproducts (3).
  • Cell division and immune function: Asparagine supports cell division and the growth of immune cells, which is necessary for an effective immune defense (4).
  • Hormone formation: Cell culture experiments (in vitro) and animal studies suggest that D-aspartic acid can play a role in testosterone synthesis and male fertility (5,6).

How does asparagine work?

The effects of asparagine in the body can be attributed to its role in the metabolism of amino acids and the regulation of proteins. Asparagine transports nitrogen between different cells and tissues, which is crucial for the build-up and breakdown of proteins and amino acids (7). In oncology, asparagine is being researched particularly in relation to cancers such as leukemia. Some tumor cells depend on external sources of asparagine, and by using enzymes that break down asparagine, researchers attempt to inhibit the growth of cancer cells (8).

Intake and Occurrence

Asparagine is present in the body as a non-essential amino acid, which means that the body can produce it itself. However, it is also found in a wide variety of foods, including asparagus, which gave the amino acid its name due to its high asparagine content, and legumes such as soybeans, lentils, and peas. Animal products such as meat, milk, and eggs are also rich in asparagine.

What risks does the use of asparagine involve?

Although asparagine is important for the body, there are some aspects that must be considered in connection with its use and processing:

  • Acrylamide formation: When carbohydrate-rich foods are prepared at high temperatures (e.g., deep-frying or baking), asparagine can react with sugars and form acrylamide. Acrylamide is a potentially carcinogenic substance found particularly in strongly heated starchy foods such as french fries and potato chips (9).
  • Cancer research: Since some cancer cells depend on asparagine, attempts are being made to inhibit tumor growth using enzymes that break down asparagine (e.g., L-asparaginase). L-asparaginase is used in certain cancers such as acute lymphoblastic leukemia to reduce the availability of asparagine (8).

Sources:

  1. Larkin, A., & Imperiali, B. (2011). The expanding horizons of asparagine-linked glycosylation. Biochemistry, 50(21), 4411–4426. https://doi.org/10.1021/bi200346n
  2. Ota, N., Shi, T., & Sweedler, J. V. (2012). D-Aspartate acts as a signaling molecule in nervous and neuroendocrine systems. Amino acids, 43(5), 1873–1886. https://doi.org/10.1007/s00726-012-1364-1
  3. Holeček M. Aspartic Acid in Health and Disease. Nutrients. 2023; 15(18):4023. https://doi.org/10.3390/nu15184023
  4. Kelly, B., & Pearce, E. L. (2020). Amino Assets: How Amino Acids Support Immunity. Cell metabolism, 32(2), 154–175. https://doi.org/10.1016/j.cmet.2020.06.010
  5. Usiello A, Di Fiore MM, De Rosa A, Falvo S, Errico F, Santillo A, Nuzzo T, Chieffi Baccari GNew Evidence on the Role of D-Aspartate Metabolism in Regulating Brain and Endocrine System Physiology: From Preclinical Observations to Clinical Applications.Int J Mol Sci.(2020-Nov-18)
  6. Di Fiore MM, Boni R, Santillo A, Falvo S, Gallo A, Esposito S, Baccari GCD-Aspartic Acid in Vertebrate Reproduction: Animal Models and Experimental Designs.Biomolecules.(2019-Sep-03)
  7. Taiz, L. & Zeiger, E. (2006): Plant Physiology, Assimilation (Biologie)
  8. Yuan, Q., Yin, L., He, J. et al. Metabolism of asparagine in the physiological state and cancer. Cell Commun Signal 22, 163 (2024). https://doi.org/10.1186/s12964-024-01540-x
  9. Bundesamt für verbraucherschutz, Was ist Acrylamid?, https://www.bvl.bund.de/DE/Arbeitsbereiche/01_Lebensmittel/02_UnerwuenschteStoffeOrganismen/04_Acrylamid/01_WasIstAcrylamid/lm_WasIstAcrylamid_basepage.html