Albumin Church Bay: 560 Lys-->Glu a new mutation detected by electrospray ionisation 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 circulating albumin. Reversed phase peptide mapping and electrospray ionisation mass spectrometry (ESI-MS) indicated that the C-terminal CNBr peptide had decreased polarity associated with a 1 Da increase in mass. Subdigestion of this peptide with trypsin and chymotrypsin revealed that the increased mass was associated with the chymotrypsin fragment VEKCCKADDKETCF (555-568) which had a mass of 1791.1 compared to 1790.2 for its normal counterpart. Sequence analysis of PCR-amplified DNA indicated an A-->G mutation at position 98 of exon 13, which causes a point mutation of 560 Lys-->Glu and results in a 1 Da mass increase.