title: Synthesis of deuterium-labelled halogen derivatives of L-tryptophan catalysed by tryptophanase.
abstract: The isotopomers of halogen derivatives of l-tryptophan (l-Trp) (4'-F-, 7'-F-, 5'-Cl- and 7'-Br-l-Trp), specifically labelled with deuterium in α-position of the side chain, were obtained by enzymatic coupling of the corresponding halogenated derivatives of indole with S-methyl-l-cysteine in (2)H2O, catalysed by enzyme tryptophanase (EC 4.1.99.1). The positional deuterium enrichment of the resulting tryptophan derivatives was controlled using (1)H NMR. In accordance with the mechanism of the lyase reaction, a 100% deuterium labelling was observed in the α-position; the chemical yields were between 23 and 51%. Furthermore, β-F-l-alanine, synthesized from β-F-pyruvic acid by the l-alanine dehydrogenase reaction, has been tested as a coupling agent to obtain the halogenated deuterium-labelled derivatives of l-Trp. The chemical yield (∼30%) corresponded to that as observed with S-methyl-l-cysteine but the deuterium label was only 63%, probably due to the use of a not completely deuterated incubation medium.
authors.affiliation: a Department of Chemistry , University of Warsaw , Warsaw , Poland.
authors.forename: Elżbieta
authors.initials: E
authors.lastname: Winnicka
authors.affiliation: a Department of Chemistry , University of Warsaw , Warsaw , Poland.
authors.forename: Jolanta
authors.initials: J
authors.lastname: Szymańska
authors.affiliation: a Department of Chemistry , University of Warsaw , Warsaw , Poland.|b Second Faculty of Medicine , Medical University of Warsaw , Warsaw , Poland.
authors.forename: Marianna
authors.initials: M
authors.lastname: Kańska
mesh_terms: D050788:Alanine Dehydrogenase / Q000737:chemistry*; D001412:Bacillus subtilis / Q000201:enzymology; D055162:Biocatalysis; D003903:Deuterium; D004926:Escherichia coli / Q000201:enzymology; D006219:Halogens / Q000737:chemistry*; D007553:Isotope Labeling; D019275:Radiopharmaceuticals / Q000138:chemical synthesis* / Q000737:chemistry; D014364:Tryptophan / Q000031:analogs & derivatives* / Q000737:chemistry; D014368:Tryptophanase / Q000737:chemistry*
chemical_list: D006219:Halogens; D019275:Radiopharmaceuticals; D014364:Tryptophan; D003903:Deuterium; D050788:Alanine Dehydrogenase; D014368:Tryptophanase
keywords: amino acids; deuterated compounds; hydrogen-2; synthesis