ANALYSIS OF HUMAN SERUM-ALBUMIN VARIANTS BY MASS-SPECTROMETRIC PROCEDURES

A new strategy for the structural characterisation of human albumin va riants has been developed which makes extensive use of mass spectromet ric methodologies. The rationale behind the method is to provide a rap id and effective screening of the entire albumin structure. The first step in this strategy consists in the attempt to determine the accurat e molecular mass of the intact variant by electrospray mass spectromet ry often providing a first indication on the presence of the variant. An HPLC procedure has been developed to isolate all the seven fragment s generated by CNBr hydrolysis of HSA in a single chromatographic step . A rapid screening of the entire albumin structure is achieved by the ESMS analysis of the peptide fragments and the protein region(s) carr ying the structural abnormality is identified by its anomalous mass va lue(s). Mass mapping of the col-responding CNBr peptide, either by Fas t Atom Bombardment Mass Spectrometry (FABMS) or by Matrix Assisted Las er Desorption Ionisation Mass Spectrometry (MALDIMS), leads to the def inition of the site and the nature of the variation. This combined str ategy was applied to the structural characterisation of three HSA gene tic variants and provided to be an effective procedure for the rapid a ssessment of their structural modifications showing considerable advan tages over the classical approach. (C) 1998 Elsevier Science B.V.