Lin Shu-Yao, Shih Shu-Hung, Wu Deng-Chyang, Lee Yi-Chern, Wu Chen-I, Lo Li-Hua, Shiea Jentaie
Department of Chemistry, National Sun Yat-Sen University, Kaohsiung, Taiwan.
Rapid Commun Mass Spectrom. 2007;21(20):3311-6. doi: 10.1002/rcm.3217.
In this study, we discover that hemoglobins (Hb), highly water-soluble globular proteins that are the most predominant proteins detected by matrix-assisted laser desorption ionization/time-of-flight (MALDI-TOF) mass spectrometry in blood, can be used as protein biomarkers for fecal occult blood (FOB). Hemoglobins were extracted from the feces with pure water and separated from the solids in feces through centrifugation. Singly charged molecular ions of Hb-related alpha chains (theoretical MW: 15 126) and beta chains (theoretical MW: 15 867) were detected by MALDI-TOF operated in linear mode using 4-hydroxy-alpha-cyanocinnamic acid (alpha-CHC) as the matrix (with a volumetric ratio of 1:1). The detection limit of FOB using this method is estimated to be lower than 0.1 microg blood per mg of feces, which is approximately 10 to 100 times lower than that of the conventional chemical approaches. The foods and dietary supplements that commonly interfere with the conventional chemical assays of FOB - such as animal blood food products and tablets containing iron and vitamin C - do not interfere with the detection of Hb biomarkers during MALDI-TOF analysis.
在本研究中，我们发现血红蛋白（Hb），即高度水溶性的球状蛋白，是血液中通过基质辅助激光解吸电离/飞行时间（MALDI-TOF）质谱检测到的最主要的蛋白质，可作为粪便潜血（FOB）的蛋白质生物标志物。血红蛋白用纯水从粪便中提取，并通过离心从粪便中的固体物质中分离出来。使用4-羟基-α-氰基肉桂酸（α-CHC）作为基质（体积比为1:1），以线性模式运行的MALDI-TOF检测到了与Hb相关的α链（理论分子量：15 126）和β链（理论分子量：15 867）的单电荷分子离子。使用该方法检测FOB的检测限估计低于每毫克粪便0.1微克血液，这比传统化学方法低约10至100倍。通常会干扰FOB传统化学检测的食物和膳食补充剂——如动物血制品以及含铁和维生素C的片剂——在MALDI-TOF分析过程中不会干扰Hb生物标志物的检测。
