兴奋剂生长激素的MALDI-TOF质谱研究

Analysis of Doping Growth Hormone by MALDI-TOF MS

采用基质辅助激光解吸/电离飞行时间质谱(MALDI-TOF MS)法对生长激素(GH)标准品和国产GH制剂进行比对研究。在完整分子的相对分子质量测定中,GH的精确分子质量为22124u,检测灵敏度达74fmol。实验还发现1种GH制剂的相对分子质量为22254u,质量数比理论质量多131u,经胰蛋白酶解产物的二级质谱测序证实是N端多一甲硫酸残基(Met)的GH。GH酶解后的肽段样品可以鉴定出8个GH肽段,覆盖率为45.5%,Mascot蛋白谱库检索蛋白质评分值为132,蛋白质置信区间为100%。测序结果说明,N端的甲硫酸残基可以作为鉴定外源GH的分子标记。

The growth hormone（GH） standard protein and preparations were analyzed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry（MALDI-TOF MS）. The molecular weight of the intact GH was 22 124 u, and the sensitivity was 74 fmol. Another GH preparation shows that the molecular weight is 22 254 u. The difference is 131 u compared with the OH standard protein. The secondary mass spectra of the trypsin digested peptides confirms that there is a methionine residue on the N-terminal. The eight digested products are sequenced by TOF/TOF, and the recoveries are 45.5%. The protein score is 132, and protein confidence interval is 100% by Mascot protein library. The result indicates that methionine on the N-terminal can be used as the molecular marker to distinguish exogenous GH.