title: Methods for the enzymatic synthesis of tyrosine and phenylalanine labeled with nitrogen-13.
abstract: L-[13N]Tyrosine and L-[13N]phenylalanine were synthesized using immobilized enzymes by two methods. In method 1, [13N]ammonia is converted to L-[13N]glutamate; transamination with p-hydroxyphenylpyruvate yields L-[13N]tyrosine. [13N]Tyrosine is separated from other labeled intermediates on a Poropak Q column. In method 2, phenylalanine dehydrogenase catalyzes the reversible reductive [13N]amination of either phenylpyruvate or p-hydroxyphenylpyruvate to form L-[13N]phenylalanine or L-[13N]tyrosine, respectively. The feasibility of labeling DOPA and tryptophan with 13N was also demonstrated.
authors.affiliation: Biophysics Laboratory, Memorial Sloan-Kettering Cancer Center, New York, NY 10021.
authors.forename: A S
authors.initials: AS
authors.lastname: Gelbard
authors.forename: A J
authors.initials: AJ
authors.lastname: Cooper
authors.forename: Y
authors.initials: Y
authors.lastname: Asano
authors.forename: E
authors.initials: E
authors.lastname: Nieves
authors.forename: S
authors.initials: S
authors.lastname: Filc-Dericco
authors.forename: K C
authors.initials: KC
authors.lastname: Rosenspire
mesh_terms: D004800:Enzymes, Immobilized; D007553:Isotope Labeling / Q000379:methods*; D009590:Nitrogen Radioisotopes; D010649:Phenylalanine; D014443:Tyrosine
chemical_list: D004800:Enzymes, Immobilized; D009590:Nitrogen Radioisotopes; D014443:Tyrosine; D010649:Phenylalanine