A study of human coagulation factor XIII A-subunit by electrospray ionisation mass spectrometry

A study of factor XIII A-subunit has been made by electrospray ionisation m ass spectrometry, Factor XIII has been isolated and rigorously purified, an d the intact A-subunit protein has been analysed to confirm its molecular w eight accurately for the first time. Thrombin proteolysis of the A-subunit has been monitored and the resulting cleavage products, the activated A-sub unit protein and the Activation Peptide, have been analysed by electrospray ionisation mass spectrometry to confirm the site of proteolysis, Facile an d rapid separation of the Activation Peptide from the activated A-subunit p rotein has been achieved using simple on-line separation techniques. The mo lecular weight measurements have been repeated numerous times to provide an indication of the precision and variability of the analyses. Copyright (C) 2000 John Wiley & Sons, Ltd.