title: Electrospray mass spectrometry of a series of mixed nitrido 99gTc- heterocomplexes conjugated with bioactive molecules.
abstract: Electrospray ionization mass spectrometry (ESI-MS) was successfully employed for the identification of six nitrido technetium mixed ligand complexes with a general formula of [99gTc(N)(O,S-BID)(PNP)], where PNP represents a heterodiphosphine and O,S-BID represents a simple dianionic bidentate ligand (compounds 1-3) or a more sophisticated N-substituted O,S-cysteine framework conjugated with a bio- active molecule (BAM) (compounds 4-6). In spite of similar coordination spheres exhibited by all the complexes investigated, simple co-ordination compounds 1-3 displayed collisionally-induced fragmentation processes (MSn) different from those observed in biomolecule-containing compounds 4-6. In the latter, more decomposition channels were observed. This behavior is likely to be associated with some additional intramolecular contacts of the biomolecule (or part of the biomolecule) with pendant group(s) incorporated in the PNP-co-ligand. This view is further supported by the observations arising from both in vitro binding affinity experiments and nuclear magnetic resonance investigations. The presence of cationized forms for all compounds 1-6 and the practical lack of the [2M + Na]+ species for biomolecule-containing compounds 4-6 provided further evidence of a subtly different structural conformation.
authors.affiliation: CNR, Istituto di Scienze e Tecnologie Molecolari, Corso Stati Uniti 4, I-35127 Padova, Italy.
authors.forename: Michela
authors.initials: M
authors.lastname: Tubaro
authors.forename: Ester
authors.initials: E
authors.lastname: Marotta
authors.forename: Francesco
authors.initials: F
authors.lastname: Tisato
authors.forename: Cristina
authors.initials: C
authors.lastname: Bolzati
authors.forename: Marina
authors.initials: M
authors.lastname: Porchia
authors.forename: Fiorenzo
authors.initials: F
authors.lastname: Refosco
authors.forename: Patrizia
authors.initials: P
authors.lastname: Tomasin
authors.forename: Mario
authors.initials: M
authors.lastname: Cavazza-Ceccato
authors.forename: Pietro
authors.initials: P
authors.lastname: Traldi
mesh_terms: D001710:Biotin / Q000737:chemistry; D003545:Cysteine / Q000737:chemistry; D017672:Nitrogen Compounds / Q000032:analysis* / Q000737:chemistry; D000077489:Piperazine; D010879:Piperazines / Q000737:chemistry; D011868:Radioisotopes / Q000032:analysis / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D013667:Technetium / Q000737:chemistry; D017556:Technetium Compounds / Q000032:analysis* / Q000737:chemistry
chemical_list: D017672:Nitrogen Compounds; D010879:Piperazines; D011868:Radioisotopes; D017556:Technetium Compounds; D000077489:Piperazine; D001710:Biotin; D013667:Technetium; D003545:Cysteine