Carnosine

pH buffer

Carnosine has a pK_a value of 6.83, making it a good buffer for the pH range of animal muscles.^[8] 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),^[9] 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.

Anti-oxidant

Carnosine has been shown to scavenge reactive oxygen species (ROS) as well as alpha-beta unsaturated aldehydes formed from peroxidation of cell membrane fatty acids during oxidative stress. It also buffers pH in muscle cells, and acts as a neurotransmitter in the brain. It is also a zwitterion, a neutral molecule with a positive and negative end.^{[citation needed]}

Antiglycating

Carnosine acts as an antiglycating agent, reducing the rate of formation of advanced glycation end-products (substances that can be a factor in the development or worsening of many degenerative diseases, such as diabetes, atherosclerosis, chronic kidney failure, and Alzheimer's disease^[10]), and ultimately reducing development of atherosclerotic plaque build-up.^[11][12][13]

Geroprotective

Carnosine is considered as a geroprotector.^[14] Carnosine can increase the Hayflick limit in human fibroblasts,^[15] as well as appearing to reduce the telomere shortening rate.^[16] Carnosine may also slow aging through its anti-glycating properties (chronic glycolyating is speculated to accelerate aging).^[17]

Other

Carnosine can chelate divalent metal ions.^[11][18] It has been suggested that binding Ca²⁺ may displace protons, thereby providing a link between Ca²⁺ and H⁺ buffering. ^[19] However, there is still controversy as to how much Ca²⁺ is bound to carnosine under physiological conditions. ^[20]

Research has demonstrated a positive association between muscle tissue carnosine concentration and exercise performance.^[21][22][23] β-Alanine supplementation is thought to increase exercise performance by promoting carnosine production in muscle. Exercise has conversely been found to increase muscle carnosine concentrations, and muscle carnosine content is higher in athletes engaging in anaerobic exercise.^[21]