Walker A K, Qiu H, Wu Y, Timmons R B, Kinsel G R
Department of Chemistry and Biochemistry, University of Texas at Arlington 76019-0065, USA.
Anal Biochem. 1999 Jul 1;271(2):123-30. doi: 10.1006/abio.1999.4141.
Previous studies have shown that increases in surface-peptide binding affinity result in decreases in peptide matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS) ion signals. The present work demonstrates that, with appropriate corrections for peptide ionization efficiency under MALDI conditions, relative surface-peptide binding affinities can be assayed using the MALDI MS methodology. Peptides with a range of pI values are allowed to interact with amine-modified and carboxylic acid-modified polymer surfaces (produced by pulsed radio-frequency plasma polymerization of allyl amine and vinyl acetic acid) in buffered solutions of neutral pH. Because of the net positive and negative charges associated with the peptides and surfaces in solution, both electrostatic and hydrophilic interactions play a role in the surface-peptide interaction. Consistent with expectations, the peptide MALDI ion signals for peptides with net negative charges in solution are smaller than those for peptides with net positive charges in solution when the peptides are allowed to interact with positively charged surfaces. A reversal of the relative peptide MALDI ion signal intensities is observed when the same peptides are allowed to interact with negatively charged surfaces. Cumulatively, the results demonstrate that even modest changes in surface-peptide interactions can be comparatively probed by MALDI mass spectrometry.
先前的研究表明，表面肽结合亲和力的增加会导致肽基质辅助激光解吸/电离（MALDI）质谱（MS）离子信号的降低。目前的工作表明，在对MALDI条件下的肽电离效率进行适当校正后，可以使用MALDI MS方法测定相对表面肽结合亲和力。使一系列具有不同pI值的肽在中性pH缓冲溶液中与胺改性和羧酸改性的聚合物表面（由烯丙基胺和乙烯基乙酸的脉冲射频等离子体聚合产生）相互作用。由于溶液中肽和表面带有净正电荷和净负电荷，静电相互作用和亲水相互作用在表面-肽相互作用中都发挥作用。正如预期的那样，当肽与带正电的表面相互作用时溶液中带净负电荷的肽的MALDI离子信号小于溶液中带净正电荷的肽的MALDI离子信号。当相同的肽与带负电的表面相互作用时，会观察到相对肽MALDI离子信号强度的反转。总体而言，结果表明，即使是表面-肽相互作用的适度变化也可以通过MALDI质谱进行比较探测。
