title: Selective 13C-labelling of cyclosporin A.
abstract: Cyclosporin A is biosynthetically labelled with 13C by growing an overproducing strain of Tolypocladium inflatum on minimal media containing either [1-13C]-, [2-13C]-, [3-13C]- or [6-13C]glucose as the only carbon source. NMR analysis of the 13C-labelled peptide showed a labelling pattern in which 13C occurs at specific sites. These can be predicted by consideration of the relevant biosynthetic pathways. Quantitation of the site-specific enrichments revealed that the 13C-label incorporation is efficient and selective. Metabolic fluxes through alternative pathways can also be estimated from these results. Isotopically labelled peptides will be a very useful tool for the study of molecular interactions with their receptors.
authors.affiliation: Sandoz Pharma AG, Präklinische Forschung, Basel, Switzerland.
authors.forename: H
authors.initials: H
authors.lastname: Senn
authors.forename: C
authors.initials: C
authors.lastname: Weber
authors.forename: H
authors.initials: H
authors.lastname: Kobel
authors.forename: R
authors.initials: R
authors.lastname: Traber
mesh_terms: D000595:Amino Acid Sequence; D002247:Carbon Isotopes; D002851:Chromatography, High Pressure Liquid; D003524:Cyclosporins / Q000096:biosynthesis / Q000737:chemistry* / Q000302:isolation & purification; D005285:Fermentation; D005947:Glucose / Q000378:metabolism; D007553:Isotope Labeling / Q000379:methods; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D003904:Mitosporic Fungi / Q000378:metabolism; D008969:Molecular Sequence Data; D016339:Spectrometry, Mass, Fast Atom Bombardment; D014508:Urea / Q000378:metabolism
chemical_list: D002247:Carbon Isotopes; D003524:Cyclosporins; D014508:Urea; D005947:Glucose