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栝楼蛋白(Trichobitacin)是从栝楼(Trichosanthes kirilowii Maxim,Cucurbitaceae)中新发现的核糖体失活蛋白,分子量为27,228;pI为9.6.应用基质辅助的激光解析飞行时间质谱(MALDI-TOF-MS)和快原子轰击质谱法(FAB-MS)分别测定胰蛋白酶酶解栝楼蛋白和天花粉蛋白(Trichosanthin)的混合肽质谱,通过比较发现了一些分子量相同的肽.由于这两种蛋白质都来源于栝楼块根,同源性比较强,所以这些肽序列在两种蛋白质中基本一样;再结合蛋白质N-端自动顺序仪测定栝楼蛋白N-端的结果,确定了栝楼蛋白N-端38个氨基酸的顺序,栝楼蛋白经胰蛋白酶酶解后所得肽段用HPLC分离纯化,再用蛋白质自动顺序仪,DABITC/PITC双偶合手工法和质谱法共确定了括楼蛋白N-端,C-端等100多个氨基酸残基的序列.
Trichobitacin is a newly discovered ribosome-inactivating protein found in Trichosanthes kirilowii Maxim (Cucurbitaceae) with a molecular weight of 27,228 and a pI of 9.6. Matrix-assisted laser desorption-time of flight mass spectrometry (MALDI-TOF-MS ) And fast atom bombardment mass spectrometry (FAB-MS) were used to determine the mixed peptide mass spectrum of tryptic digesta protein and trichosanthin, respectively, and some peptides of the same molecular weight were found by comparison.As both of these proteins are derived from The results showed that these peptide sequences were almost the same in the two proteins. The results of N-terminal sequence analysis of proteins by N-terminal sequence analysis confirmed that N-terminal 38 Amino acid sequence, and the protein fragment was purified by HPLC after trypsin digestion by trypsin, and then the N-terminus and C-terminal protein were determined by automatic sequential sequencer, DABITC / PITC double coupled manual method and mass spectrometry. End more than 100 amino acid residues in the sequence.