Department of Mathematics, University of York, York YO10 5YW, UK.
Anal Chem. 2012 Nov 6;84(21):9041-8. doi: 10.1021/ac301333t. Epub 2012 Oct 15.
Collagen peptides are analyzed using a low-cost, high-throughput method for assessing deamidation using matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). For each chosen peptide, the theoretical distribution is calculated and the measured distribution for each sample compared with this to determine the extent of glutamine deamidation. The deamidation of glutamine (Q) to glutamic acid (E) results in a mass shift of +0.984 Da. Thus, from the resolution of our data, the second peak in the isotope distribution for a peptide containing one glutamine residue coincides with the first peak of the isotope distribution for the peptide in which the residue is deamidated. A genetic algorithm is used to determine the extent of deamidation that gives the best fit to the measured distribution. The method can be extended to peptides containing more than one glutamine residue. The extent of protein degradation assessed in this way could be used, for example, to assess the damage of collagen, and screen samples for radiocarbon dating and DNA analysis.
胶原蛋白肽使用一种低成本、高通量的方法进行分析，该方法使用基质辅助激光解吸/电离质谱（MALDI-MS）评估脱酰胺作用。对于每个选定的肽，计算理论分布，并将每个样品的测量分布与该分布进行比较，以确定谷氨酰胺脱酰胺作用的程度。谷氨酰胺（Q）向谷氨酸（E）的脱酰胺作用导致质量位移+0.984 Da。因此，从我们数据的分辨率来看，含有一个谷氨酰胺残基的肽的同位素分布中的第二个峰与该残基脱酰胺的肽的同位素分布中的第一个峰重合。遗传算法用于确定与测量分布拟合度最好的脱酰胺程度。该方法可以扩展到含有多个谷氨酰胺残基的肽。以这种方式评估的蛋白质降解程度可用于评估胶原蛋白的损伤，并筛选用于放射性碳测年和 DNA 分析的样品。
