Albumin Banks Peninsula: a new termination variant characterised by electrospray mass spectrometry

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• 作者：Brennan ; Stephen O. ; Fellowes ; Andrew P. ; George ; Peter M.
• 关键词：Serum albumin ; Truncation ; Electrospray mass spectrometry ; Low expression
• 刊名：Biochimica et Biophysica Acta (BBA)/Protein Structure and Molecular Enzymology
• 出版年：1999
• 出版时间：August 17, 1999
• 年：1999
• 卷：1433
• 期：1-2
• 页码：321-326
• 全文大小：291 K

文摘

Albumin Banks Peninsula is an electrophoretically fast variant that is expressed at only 2 % of the total serum albumin. Electrospray ionisation analysis indicated a mass decrease of 755 Da relative to normal albumin and carboxypeptidase A digestion, together with CNBr peptide mapping, indicated a C-terminal truncation. This was confirmed by PCR and DNA sequence analysis which showed the introduction of a new AG acceptor splice site near the 3′ end of intron 13. Predictably this results in the replacement of the C-terminal GKKLVAASQAALGL sequence by SLCSG and would be associated with an 861 Da decrease in molecular mass. We surmised that the new Cys was most probably cysteinylated as this albumin species would have a mass decrease of 742 Da and be very close to the measured value of 755 Da. Cysteinylation was confirmed when a mass decrease of 863 Da was measured between the proteins after reduction of their disulfide bonds.