Carnosine is naturally produced by the body in the liver[2] frombeta-alanine andhistidine. Likecarnitine, carnosine is composed of the root wordcarn, meaning "flesh", alluding to its prevalence in meat.[3] There are no plant-based sources of carnosine.[4] Carnosine is readily available as a synthetic nutritional supplement.
Carnosine can chelate divalent metal ions.[5] Carnosine is also considered ageroprotectant.[6]
Products containing carnosine are also used in topical preparations to reduce wrinkles on the skin.[7]
Carnosine may increase the Hayflick limit in human fibroblasts, it also appears to reduce the rate of telomere shortening.[8] This could potentially promote the growth of certain cancers that thrive due to telomere preservation.[7]
Carnosine is synthesized within the body frombeta-alanine andhistidine. Beta-alanine is a product ofpyrimidine catabolism[9] and histidine is anessential amino acid. Since beta-alanine is the limiting substrate, supplementing just beta-alanine effectively increases the intramuscular concentration of carnosine.[10][11]
Carnosine has a pKa value of 6.83, making it a goodbuffer for the pH range of animal muscles.[12] Since beta-alanine is not incorporated into proteins, carnosine can be stored at relatively high concentrations (millimolar). Occurring at 17–25 mmol/kg (dry muscle),[13] carnosine (β-alanyl-L-histidine) is an important intramuscular buffer, constituting 10-20% of the total buffering capacity in type I and II muscle fibres.
Carnosine has been shown to scavengereactive oxygen species (ROS) as well as alpha-beta unsaturatedaldehydes formed from peroxidation of cell membranefatty acids duringoxidative stress. It also buffers pH in muscle cells, and acts as a neurotransmitter in the brain. It is also azwitterion, a neutral molecule with a positive and negative end.[citation needed]
Carnosine is considered as ageroprotector.[18] Carnosine can increase theHayflick limit in humanfibroblasts,[19] as well as appearing to reduce thetelomere shortening rate.[20] Carnosine may also slow aging through its anti-glycating properties (chronic glycolyating is speculated to accelerate aging).[21]
Carnosine canchelatedivalent metal ions.[15][22] It has been suggested that binding Ca2+ may displace protons, thereby providing a link between Ca2+ and H+ buffering.[23] However, there is still controversy as to how much Ca2+ is bound to carnosine under physiological conditions.[24]
^Alan R. Hipkiss (2009). "Chapter 3: Carnosine and Its Possible Roles in Nutrition and Health".Advances in Food and Nutrition Research.
^Reddy, V. P.; Garrett, MR; Perry, G; Smith, MA (2005). "Carnosine: A Versatile Antioxidant and Antiglycating Agent".Science of Aging Knowledge Environment.2005 (18): pe12.doi:10.1126/sageke.2005.18.pe12.PMID15872311.
^Boldyrev, A. A.; Stvolinsky, S. L.; Fedorova, T. N.; Suslina, Z. A. (2010). "Carnosine as a natural antioxidant and geroprotector: From molecular mechanisms to clinical trials".Rejuvenation Research.13 (2–3):156–8.doi:10.1089/rej.2009.0923.PMID20017611.
^Shao, Lan; Li, Qing-Huan; Tan, Zheng (2004). "L-Carnosine reduces telomere damage and shortening rate in cultured normal fibroblasts".Biochemical and Biophysical Research Communications.324 (2):931–6.doi:10.1016/j.bbrc.2004.09.136.PMID15474517.
^"beta-ureidopropionate + H2O => beta-alanine + NH4+ + CO2".reactome.Archived from the original on 2013-10-23. Retrieved2020-02-08.Cytosolic 3-ureidopropionase catalyzes the reaction of 3-ureidopropionate and water to form beta-alanine, CO2, and NH3 (van Kuilenberg et al. 2004).
^Derave W, Ozdemir MS, Harris R, Pottier A, Reyngoudt H, Koppo K, Wise JA, Achten E (August 9, 2007). "Beta-alanine supplementation augments muscle carnosine content and attenuates fatigue during repeated isokinetic contraction bouts in trained sprinters".J Appl Physiol.103 (5):1736–43.doi:10.1152/japplphysiol.00397.2007.PMID17690198.S2CID6990201.
^Hill CA, Harris RC, Kim HJ, Harris BD, Sale C, Boobis LH, Kim CK, Wise JA (2007). "Influence of beta-alanine supplementation on skeletal muscle carnosine concentrations and high intensity cycling capacity".Amino Acids.32 (2):225–33.doi:10.1007/s00726-006-0364-4.PMID16868650.S2CID23988054.
^Mannion, AF; Jakeman, PM; Dunnett, M; Harris, RC; Willan, PLT (1992). "Carnosine and anserine concentrations in the quadriceps femoris muscle of healthy humans".Eur. J. Appl. Physiol.64 (1):47–50.doi:10.1007/BF00376439.PMID1735411.S2CID24590951.
^abReddy, V. P.; Garrett, MR; Perry, G; Smith, MA (2005). "Carnosine: A Versatile Antioxidant and Antiglycating Agent".Science of Aging Knowledge Environment.2005 (18): pe12.doi:10.1126/sageke.2005.18.pe12.PMID15872311.
^Boldyrev, A. A.; Stvolinsky, S. L.; Fedorova, T. N.; Suslina, Z. A. (2010). "Carnosine as a natural antioxidant and geroprotector: From molecular mechanisms to clinical trials".Rejuvenation Research.13 (2–3):156–8.doi:10.1089/rej.2009.0923.PMID20017611.
^McFarland, G; Holliday, R (1994). "Retardation of the Senescence of Cultured Human Diploid Fibroblasts by Carnosine".Experimental Cell Research.212 (2):167–75.doi:10.1006/excr.1994.1132.PMID8187813.
^Shao, Lan; Li, Qing-Huan; Tan, Zheng (2004). "L-Carnosine reduces telomere damage and shortening rate in cultured normal fibroblasts".Biochemical and Biophysical Research Communications.324 (2):931–6.doi:10.1016/j.bbrc.2004.09.136.PMID15474517.
