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目的 采用质谱技术研究许旺细胞源神经营养蛋白 (SDNP)的分子结构。 方法 将纯化后保持活性的SDNP ,用TPCK 胰蛋白酶酶解 ,行激光飞行时间质谱检测 ,测定肽质量指纹质谱 ,以及碎片结构分析测序列 ,然后在相应的质谱数据库中检索。 结果 (1)激光飞行时间质谱测得完整样品中SDNP的分子量 ;(2 )同时测得酶解样品中几十个肽段的质谱图 ,各肽段的分子量亦相应测出 ,检测8个肽段参数 ,通过蛋白质谱数据库MS Fit检索未发现有蛋白 10 0 %吻合 ,Hypotheticalprotein有 5个肽段符合 (吻合率 62 % ) ;(3 )取酶解质谱中的 2 3 0 5Da片段经质谱碎片分析得到若干碎片离子类型图谱 ,从获得的参数通过蛋白质谱数据库MS Tag检索得出该片段的氨基酸序列。 结论 通过质谱检测 ,许旺细胞源神经营养蛋白的相对分子质量是 66× 10 3 ,部分片段的氨基酸序列为EPVKKVTNSRRAKP TKPNGHIAN。
Objective To study the molecular structure of Schwann cell-derived neurotrophic protein (SDNP) by mass spectrometry. Methods Purified and purified SDNP was digested with TPCK trypsin and detected by laser-time of flight mass spectrometry. Peptide mass fingerprinting (MS / MS) mass spectrometry and fragmentation analysis were used to search the corresponding mass spectrometry database. Results (1) The molecular weight of SDNP in the intact sample was measured by laser time-of-flight mass spectrometry. (2) The mass spectra of dozens of peptides in the enzymolysis samples were also measured. The molecular weights of each peptide were also measured. The results showed that there was no coincidence of 100% of the proteins found in MS Fit by MS Fit search, and 5 of Hypothetical protein matched (62% of coincidences). (3) The fragment of 205 ODa in enzyme-resolved mass spectrometry A number of fragment ion profiles were obtained and the amino acid sequence of the fragment was obtained from the acquired parameters by MS Tag search. Conclusion The relative molecular mass of Schwann cell-derived neurotrophic protein is 66 × 10 3 by mass spectrometry. The amino acid sequence of some fragments is EPVKKVTNSRRAKP TKPNGHIAN.