In-gel proteolytic cleavage was performed automatically in the`Progest' as described (Houthaeve et al., 1997) [Genomic Solutions Cambridge (http://www.genomicsolutions.com)] and the peptides obtained were analysed on a Bruker REFLEX MALDI mass spectrometer (Bruker Analytik, Germany) (Jensen et al., 1996b) . Proteins were identi®ed by peptide mass ®ngerprinting (Jensen et al., 1997) using the program PeptideSearch (http://www.narrador.embl-heidelberg.de/Services/ PeptideSearch/PeptideSearchIntro.html.