Acquired and congenital fast albumin bands; insights from electrospray TOF analysis of whole plasma into drug binding and albumin recycling

作者：Brennan Stephen O^*; Mackay Richard

来源：Clinical Biochemistry, 2016, 49(1-2): 180-182.

DOI：10.1016/j.clinbiochem.2015.09.013

• Albumin
• Electrophoresis
• Serum mass spectrometry
• Acquired and genetic modifications
• Flucloxacillin
• Albumin recycling

Objectives: To define the underlying cause of unusual fast albumin bands detected on plasma protein electrophoresis of two patients.
Method: Plasma was examined by electrospray time-of-flight mass spectrometry (TOF MS) to assess the possibility of congenital or acquired structural modifications.
Results: In one patient whole protein MS indicated a drop of 486 Da in the mass of 5.1% of the albumin molecules. This and the presence of an additional minor product (65,806 Da) lacking a C-terminal phenylalanine (-147 Da) indicated that this was albumin Rugby Park; an electrophoretically fast albumin variant caused by a splice site mutation (GT > CT) in intron 13 of the albumin gene. The second patient had an acquired alteration with a drift of albumin mobility to the anode. This severely ill patient was on intra venous antibiotics and electrospray TOF MS showed a stuttered repetition of the 66,439/66,558 Da albumin isoforms at multiples of 455-459 Da corresponding to the covalent attachment of 1, 2, 3 and 4 molecules of flucloxacillin. This modification of +455 Da was also detected in a control on a 1 g/day oral dose of flucloxacillin.
Conclusion: Both aberrations were associated with diminished albumin concentrations. The C-terminal truncation of Rugby Park (albumin, 29 g/l) likely interferes with receptor binding and albumin scavenging, while the 20 g/l albumin in the second patient was mostly due to renal disease. In both cases electrospray TOF MS proved a rapid (5 min) sensitive (0.2 mu l plasma) and highly informative way of analysing whole plasma or serum.

• 出版日期2016-1