Polymorphism and Identification of Metallothionein Isoforms by Reversed-Phase HPLC with On-Line Ion-Spray Mass Spectrometric Detection

H. Chassaigne (1) , Ryszard Lobinski (1, 2)

1 LCABIE - Laboratoire de Chimie Analytique Bio-Inorganique et Environnement
2 IPREM - Institut des sciences analytiques et de physico-chimie pour l'environnement et les materiaux

Microbore reversed-phase HPLC with on-line ion-spray mass spectrometric detection is proposed for a study of polymorphism of rabbit liver metallothionein (MTRL) and its major isoforms MT-1 and MT-2. Separation conditions had been optimized until each Chromatographic peak could be attributed to a single metalloprotein species, of which the molecular mass could be determined by ion-spray MS. At the optimized conditions (elution with the gradient 5-8% of acetonitrile within 50 min using a 5 mM acetate buffer at pH 6), the chromatogram of MTRL showed five peaks, whereas those of MT-1 and MT-2 showed nine and seven different peaks, respectively. The on-line determination of the molecular masses (±1 Da) of the compounds eluted permits the unambiguous cataloguing and further referencing of putative and true MT subisoforms. The results obtained are compared with those obtained by direct ion-spray MS of the MT preparations at different pHs, with a goal to identify possible Chromatographic artifacts. Metals (Cd, Cu) in the eluted complexes were studied by HPLC with on-line ICP MS detection.

Domaines: Chimie analytique

H. Chassaigne, Ryszard Lobinski. Polymorphism and Identification of Metallothionein Isoforms by Reversed-Phase HPLC with On-Line Ion-Spray Mass Spectrometric Detection. Analytical Chemistry, 1998, 70 (13), pp.2536--2543. ⟨hal-01559807⟩