L-лейцин

Описание

Small, white, lustrous plates, or a white, crystalline powder, with a slightly bitter taste. One g dissolves in about 40 mL of water and in about 100 mL of acetic acid. It is sparingly soluble in alcohol, but is soluble in dilute hydrochloric acid and in solutions of alkali hydroxides and carbonates. ι-Leucine may be synthesized by bromination, followed by amination of isocaproic acid; via the acetamidomalonic ester; by isolation from gluten, casein, keratin; from hydantoin.

Химические свойства

L-Leucine is odorless and has a slightly bitter taste. L-Leucine is a branched-chain, essential amino acid that stimulates muscle protein synthesis.

Вхождение

Reported found as a constituent in proteins; also present in the free state in the human body

Использование

L-Leucine plays a vital role in hemoglobin formation, protein synthesis and metabolic functions. It assists the growth and repair of muscle and bone tissue. It is used in the treatment of amyotrophic lateral sclerosis - Lou Gehrig's disease. It prevents the breakdown of muscle proteins after trauma or severe stress and may be beneficial for individuals with phenylketonuria. It is also used as a food additive and flavor enhancer. Further, it is used to preserve muscle glycogen.

Подготовка

By bromination followed by amination of isocaproic acid; via the acetamidomalonic ester; by isolation from gluten, casein, keratin; from hydantoin.

Методы производства

Leucine is produced microbially by incubating an amino-acidproducing microorganism including but not exclusive to Pseudomonas, Escherichia, Bacillus, or Staphylococcus in the presence of oxygen and a hydrocarbon. The nutrient medium should contain an inhibitory amount of a growth inhibitor that is a chemically similar derivative of leucine (e.g. methylallylglycine, a-hydrozinoisocaproic acid, or b-cyclopentanealanine) to inhibit the growth of the organism except for at least one mutant that is resistant to the inhibitory effect. The resistant mutant is then isolated and grown in the presence of oxygen and the hydrocarbon in the absence of the inhibitor. The mutant cells are then harvested and a nutrient medium is formed that includes a hydrocarbon as the sole source of carbon. Finally, the harvested cells are incubated in the medium in the presence of oxygen.

Определение

ChEBI: The L-enantiomer of leucine.

Фармацевтические приложения

Leucine is used in pharmaceutical formulations as a flavoring agent. It has been used experimentally as an antiadherent to improve the deagglomeration of disodium cromoglycate micro-particles and other compounds in inhalation preparations; and as a tablet lubricant. Leucine copolymers have been shown to successfully produce stable drug nanocrystals in water.

Безопасность

Leucine is an essential amino acid and is consumed as part of a normal diet. It is generally regarded as a nontoxic and nonirritant material. It is moderately toxic by the subcutaneous route.
LD50 (rat, IP): 5.379 g/kg

хранилище

Leucine is sensitive to light and moisture, and should be stored in an airtight container in a cool, dark, dry place.

Методы очистки

Likely impurities are isoleucine, valine, and methionine. Crystallise L-leucine from water by adding 4 volumes of EtOH. It sublimes at 180-188o/0.3mm with 99.1% recovery, and unracemised [Gross & Gradsky J Am Chem Soc 77 1678 1955]. [Greenstein & Winitz The Chemistry of the Amino Acids J. Wiley, Vol 3 p 2075-2094 1961, Kameda et al. J Pharm Soc Jpn 78 763 1958, Beilstein 4 IV 2738.]

Несовместимости

Leucine is incompatible with strong oxidizing agents.

Регуляторный статус

Included in the FDA Inactive Ingredients Database (IV infusion; oral tablets). Included in nonparenteral medicines licensed in the UK.