ALBUMIN CHURCH BAY - 560-LYS-]GLU A NEW MUTATION DETECTED BY ELECTROSPRAY-IONIZATION MASS-SPECTROMETRY

Albumin Church Bay is a fast migrating genetic variant of human serum albumin which, in a heterozygous subject, formed about 50% of the circ ulating albumin. Reversed phase peptide mapping and electrospray ionis ation mass spectrometry (ESI-MS) indicated that the C-terminal CNBr pe ptide had decreased polarity associated with a 1 Da increase in mass. Subdigestion of this peptide with trypsin and chymotrypsin revealed th at the increased mass was associated with the chymotrypsin fragment VE KCCKADDKETCF (555-568) which had amass of 1791.1 compared to 1790.2 fo r its normal counterpart. Sequence analysis of PCR-amplified DNA indic ated an A --> G mutation at position 98 of exon 13, which causes a poi nt mutation of 560 Lys --> Glu and results in a 1 Da mass increase. (C ) 1998 Elsevier Science B.V.