Department of Chemistry, The University of Adelaide, South Australia, 5005, Australia.
Phys Chem Chem Phys. 2010 Nov 7;12(41):13400-7. doi: 10.1039/c0cp00717j. Epub 2010 Sep 13.
Negative ion electrospray mass spectra of the peptides produced by tryptic and chymotrypsin digests of bovine insulin, and from the tryptic digest of lysozyme identify at least 80% of the sequences of these proteins. In particular, negative ion mass spectrometry identifies and positions disulfide moieties, and is the method of choice for identifying this post-translational modification in these two proteins. Intramolecular disulfide functionality is identified by the fragmentation (M - H)(-)- H(2)S(2) in a digest peptide, and CID of that fragment anion provides amino acid sequencing information. Digest peptides containing an intermolecular disulfide structure undergo facile and diagnostic cleavages. Each cleavage produces a peptide fragment from which CID MS/MS data provide sequencing information.
牛胰岛素胰蛋白酶和糜蛋白酶消化产物以及溶菌酶胰蛋白酶消化产物的负离子电喷雾质谱鉴定出这些蛋白质的至少 80%的序列。特别是，负离子质谱鉴定并定位了二硫键部分，是这两种蛋白质中鉴定这种翻译后修饰的首选方法。分子内二硫键功能通过消化肽中的 (M - H)(-)- H(2)S(2) 片段来识别，并且该片段阴离子的 CID 提供氨基酸测序信息。含有分子间二硫键结构的消化肽易于发生并具有诊断性的裂解。每个裂解产生一个肽片段，其中 CID MS/MS 数据提供测序信息。
