Occurrence
Reported found as a constituent in proteins; also present in the free state in the human body
Definition
ChEBI: The L-enantiomer of leucine.
Preparation
By bromination followed by amination of isocaproic acid; via the acetamidomalonic ester; by isolation from gluten,
casein, keratin; from hydantoin.
Production Methods
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.
General Description
This certified reference material (CRM) is produced and certified in accordance with ISO/IEC 17025 and ISO 17034. This CRM is traceable to primary material from an NMI, e.g. NIST or NMIJ.
Certified content by quantitative NMR incl. uncertainty and expiry date are given on the certificate.
Download your certificate at: http://www.sigma-aldrich.com.
Pharmaceutical Applications
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.
Biochem/physiol Actions
Leucine is a non-glucogenic, essential amino acid. It is a branched-chain amino acid that is a structural component of proteins. Leucine positively influences insulin release to eliminate toxic sugars out of the blood. The degradation of leucine leads to the formation of ketone bodies.
Safety
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
storage
Leucine is sensitive to light and moisture, and should be stored in an
airtight container in a cool, dark, dry place.
Purification Methods
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.]
Incompatibilities
Leucine is incompatible with strong oxidizing agents.
Regulatory Status
Included in the FDA Inactive Ingredients Database (IV infusion; oral
tablets). Included in nonparenteral medicines licensed in the UK.
