L-Alanine

SRP: At the time of review, criteria for land treatment or burial (sanitary landfill) disposal practices are subject to significant revision. Prior to implementing land disposal of waste residue (including waste sludge), consult with environmental regulatory agencies for guidance on acceptable disposal practices.

TERRESTRIAL FATE: Based on a classification scheme(1), Koc values ranging from 31.7-65(2), indicate that L-alanine is expected to have very high to high mobility in soil(SRC). Measured pKa values of 2.34 (carboxylic acid) and 9.69 (primary amine)(3), indicate that this compound will exist as a zwitterion in the environment. Volatilization of L-alanine from moist soil surfaces is not expected to be an important fate process(SRC) since ionic compounds do not volatilize. L-Alanine is not expected to volatilize from dry soil surfaces(SRC) based upon an estimated vapor pressure of 1.1X10-7 mm Hg at 25 °C(SRC), determined from a fragment constant method(4). L-Alanine is expected to biodegrade in soil based on 61-81% loss of C-14 labeled carbon as CO2 from loam and sandy loam soil after 1 week(5).

AQUATIC FATE: Based on a classification scheme(1), measured Koc values ranging from 31.7-65(2), indicate that L-alanine is not expected to adsorb to suspended solids and sediment(SRC). Measured pKa values of 2.34 (carboxylic acid) and 9.69 (primary amine)(3), indicate that this compound will exist as a zwitterion in the environment. Volatilization of L-alanine from water surfaces is not expected to be an important fate process(SRC) since ionic compounds do not volatilize. According to a classification scheme(4), a BCF of 0.004(SRC), from its log Kow of -2.85(5) and a regression-derived equation(6), suggests the potential for bioconcentration in aquatic organisms is low(SRC). L-Alanine is expected to biodegrade in water based on 96% degradation after 23 days measured in a screening test using an activated sludge inoculum(7).

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), L-alanine, which has an estimated vapor pressure of 1.1X10-7 mm Hg at 25 °C(SRC), determined from a fragment constant method(2), is expected to exist in both the vapor and particulate phases in the ambient atmosphere. Vapor-phase L-alanine is degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals(SRC); the half-life for this reaction in air is estimated to be 11 hours(SRC), calculated from its rate constant of 3.5X10-11 cu cm/molecule-sec at 25 °C(SRC) that was derived using a structure estimation method(3). Particulate-phase L-alanine may be removed from the air by wet or dry deposition(SRC). L-Alanine does not contain chromophores that absorb at wavelengths >290 nm and therefore is not expected to be susceptible to direct photolysis by sunlight(4).

Safe in the present practices of use and concentration. Ingredient, concentration, and use information are available in documents discoverable at https://cir-reports.cir-safety.org

L-Alanine is a non-essential amino acid that occurs in high levels in its free state in plasma. It is produced from pyruvate by transamination. It is involved in sugar and acid metabolism, increases immunity, and provides energy for muscle tissue, brain, and the central nervous system. BCAAs are used as a source of energy for muscle cells. During prolonged exercise, BCAAs are released from skeletal muscles and their carbon backbones are used as fuel, while their nitrogen portion is used to form another amino acid, Alanine. Alanine is then converted to Glucose by the liver. This form of energy production is called the Alanine-Glucose cycle, and it plays a major role in maintaining the body's blood sugar balance.

Typical raw materials for the isolation of amino acids include swine bristles, blood meal, collagen, and horn chips(1). The content in percentage of dried substance for these materials is 4%, 7.1%, 10%, and 4.2%, respectively(1). /Amino acids/

Koc values of 35.7 and 31.7-65 have been measured for alanine in surface sediment(1). According to a classification scheme(2), these Koc values suggest that L-alanine is expected to have very high to high mobility in soil. Measured pKa values of 2.34 (carboxylic acid) and 9.69 (primary amine)(3), indicate that this compound will exist as a zwitterion in the environment.

/ALTERNATIVE and IN VITRO TESTS/ The amino acid L-alanine has been shown to exert long-term cytoprotection by as yet unidentified molecular mechanisms. Using cultured human endothelial cells (ECV 304), the present study investigates the effect of L-alanine on hydrogen peroxide-mediated cytotoxicity and expression of the antioxidant stress proteins, heme oxygenase-1 (HO-1) and ferritin. Pretreatment with L-alanine (0.3-3mM) protected endothelial cells from hydrogen peroxide-dependent cytotoxicity and increased the surviving endothelial cell fraction by 76%. The described protection was associated with a significant induction of heme oxygenase activity and ferritin protein synthesis. A protective effect similar to L-alanine was observed when preincubating the cells with iron-free apoferritin or the antioxidant HO-1 product, bilirubin. The present study demonstrates that L-alanine stimulates expression of the antioxidant defense proteins HO-1 and ferritin in endothelial cells. Increased heme oxygenase activity and ferritin expression improve endothelial dysfunction suggesting an antiatherogenic potential of L-alanine.

/OTHER TOXICITY INFORMATION/ The response to a primed constant infusion of alanine 2 mg/kg/min on glucose and urea kinetics in 4 healthy overnight fasted subjects was /studied/ by use of concurrent primed infusions of 6,6-d2-glucose and radiolabeled urea. When no alanine was infused, plateaus in glucose and urea concn and enrichment were maintained for the final 3 hr of 4 hr infusion of tracers. When alanine was infused over the final 2 hr of a second protocol, urea enrichment decr significantly, indicating an incr in urea production corresponding to a potential incr in glucogenesis from alanine of 20%. The alanine infusion had no effect on either the plasma concn or enrichment of glucose, suggesting hepatic glucose output was not affected.

AEROBIC: An initial alanine concentration of 333 mg/L in an activated sludge inoculum (71.4 mL/L) was reduced by 96% after 23 days as measured by BOD(1). L-Alanine, at an initial concentration of 100 mg/L, reached 40-53% of its theoretical oxygen demand after 3.3-3.75 days in an activated sludge inoculum at 30 mg/L(2). L-Alanine, at an initial concentration of 500 mg/L, reached 96.2-96.6% of its theoretical oxygen demand after 5 days in an activated sludge inoculum at 1,296-1,316 mg/L(3). Alanine at 500 mg/L reached 40% of its theoretical oxidation after 12 hours of aeration in acclimated activated sludge(4). alpha-DL-Alanine, at an initial concentration of 500 mg/L, reached 43% of its theoretical oxygen demand after 24 hours in an activated sludge inoculum at 2,500 mg/L(5). alpha-DL-Alanine at 2-10 mg/L reached approximately 39% of its theoretical oxygen demand after 5 days in tests using a sea water dilution method and a standard dilution method(6). A proposed pathway for the metabolic degradation of alanine in activated sludge is through hydrolysis to lactic acid followed by oxidation through pyruvic acid to formic acid and acetic acid followed by complete oxidation(7).

AEROBIC: C-14 labeled alanine was applied at 3,000 ppm to a closed, constantly aerated system in Steinbeck loam (pH 5.0) and Greenfield sandy loam (pH 7.0)(1). After 1 week, 61-81% of the carbon applied to the Steinbeck loam and 79% of the carbon applied to the Greenfield sandy loam was lost as CO2(1).

ANAEROBIC: Alanine was listed among organic compounds that were utilized as energy substrates in batch cultures inoculated with activated sludge (2 mg dry weight/L) under chlorate-reducing conditions(1). Additional information was not provided(1).

An estimated BCF of 0.004 in fish was calculated for L-alanine(SRC), using an estimated log Kow of -2.85(1) and a regression-derived equation(2). According to a classification scheme(3), this BCF suggests the potential for bioconcentration in aquatic organisms is low(SRC).

Measured pKa values of 2.34 (carboxylic acid) and 9.69 (primary amine)(1), indicate that this compound will exist as a zwitterion in the environment. Volatilization of L-alanine from moist soil or water surfaces is not expected to be an important fate process(SRC) since ionic compounds do not volatilize. L-Alanine is not expected to volatilize from dry soil surfaces(SRC) based upon a an estimated vapor pressure of 1.1X10-7 mm Hg(SRC), determined from a fragment constant method(2).

L-Alanine is a food additive permitted for direct addition to food for human consumption, as long as 1) the quantity of the substance added to food does not exceed the amount reasonably required to accomplish its intended physical, nutritive, or other technical effect in food, and 2) any substance intended for use in or on food is of appropriate food grade and is prepared and handled as a food ingredient.