L-(1-11C)leucine: routine synthesis by enzymatic resolution
L-(1-11C)leucine, suitable for the determination of cerebral protein synthesis rates in man using positron emission tomography, has been synthesized using a modified Bucherer-Strecker reaction sequence. The isolation of the pure L-amino acid isomer from the enantiomeric mixture, initially obtained using either an open or closed reaction vessel, was achieved using a D-amino acid oxidase/catalase enzyme complex immobilized on a Sepharose support. The O2 required by the D-amino acid oxidase as the hydrogen acceptor was supplied by catalase. The L-(1-11C)leucine was obtained with a radiochemical purity of greater than 99% and with a radiochemical yield of 25%. Using a remote, semiautomated synthesis system, typical production time was 30-40 min after preparation of H11CN. The use of immobilized enzymes for rapid and effective resolution of amino acid enantiomers eliminates the possibility of protein contamination and assures the production of a sterile, pyrogen-free product.
- Research Organization:
- University of California, Los Angeles
- OSTI ID:
- 5557367
- Journal Information:
- J. Nucl. Med.; (United States), Journal Name: J. Nucl. Med.; (United States) Vol. 24:6; ISSN JNMEA
- Country of Publication:
- United States
- Language:
- English
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62 RADIOLOGY AND NUCLEAR MEDICINE
AMINO ACIDS
ANIMAL TISSUES
BETA DECAY RADIOISOTOPES
BETA-PLUS DECAY RADIOISOTOPES
BODY
BRAIN
CARBON 11
CARBON ISOTOPES
CARBOXYLIC ACIDS
CENTRAL NERVOUS SYSTEM
CHEMICAL PREPARATION
CHEMISTRY
COMPUTERIZED TOMOGRAPHY
DIAGNOSTIC TECHNIQUES
DRUGS
EMISSION COMPUTED TOMOGRAPHY
EVEN-ODD NUCLEI
IMMOBILIZED ENZYMES
ISOMERS
ISOTOPES
LABELLED COMPOUNDS
LABELLING
LEUCINE
LIGHT NUCLEI
MINUTES LIVING RADIOISOTOPES
NERVE TISSUE
NERVOUS SYSTEM
NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANS
POSITRON COMPUTED TOMOGRAPHY
RADIOCHEMISTRY
RADIOISOTOPES
RADIOPHARMACEUTICALS
SYNTHESIS
TISSUES
TOMOGRAPHY