title: Protein labeling with the labeling precursor [(18)F]SiFA-SH for positron emission tomography.
abstract: Proteins previously derivatized with the cross-coupling reagent sulfo-SMCC (4-(N-maleimidomethyl)cyclohexane-1-carboxylic acid 3-sulfo-N-hydroxy-succinimide ester sodium salt) can be easily labeled in high radiochemical yields with the silicon-fluoride acceptor (SiFA) reagent [(18)F]SiFA-SH, obtained via isotopic exchange, by thiol-maleimide coupling chemistry (n = 10). The specific activity of SiFA-SH obtained in a one-step labeling reaction was > 18.5 GBq μmol(-1) (> 500 Ci mmol(-1)). The number of SiFA building blocks per protein molecule is defined by the previously introduced number of maleimide groups, which can be determined by a simple and convenient Ellman's assay. Not more than two maleimide groups are introduced using sulfo-SMCC, thereby keeping the modification of the protein low and preserving its biological activity.
authors.affiliation: Molecular Imaging and Radiochemistry, Medical Faculty Mannheim, Department of Clinical Radiology and Nuclear Medicine, Heidelberg University, Mannheim, Germany.
authors.forename: Björn
authors.initials: B
authors.lastname: Wängler
authors.forename: Alexey P
authors.initials: AP
authors.lastname: Kostikov
authors.forename: Sabrina
authors.initials: S
authors.lastname: Niedermoser
authors.forename: Joshua
authors.initials: J
authors.lastname: Chin
authors.forename: Katy
authors.initials: K
authors.lastname: Orchowski
authors.forename: Esther
authors.initials: E
authors.lastname: Schirrmacher
authors.forename: Liuba
authors.initials: L
authors.lastname: Iovkova-Berends
authors.forename: Klaus
authors.initials: K
authors.lastname: Jurkschat
authors.forename: Carmen
authors.initials: C
authors.lastname: Wängler
authors.forename: Ralf
authors.initials: R
authors.lastname: Schirrmacher
mesh_terms: D002851:Chromatography, High Pressure Liquid; D005462:Fluorine Radioisotopes / Q000737:chemistry*; D007553:Isotope Labeling / Q000379:methods*; D017646:Organosilicon Compounds / Q000138:chemical synthesis*; D049268:Positron-Emission Tomography / Q000379:methods*; D011506:Proteins / Q000737:chemistry*
chemical_list: C539566:4-(di-tert-butyl(18F)fluorosilyl)benzenethiol; D005462:Fluorine Radioisotopes; D017646:Organosilicon Compounds; D011506:Proteins