基体辅助激光解吸电离飞行时间质谱法测定钙调素的分子量

The molecular weight of bovine brain CaM, intracellular CaM and extracellularCaM of cauliflower have been determined for the first time by Matrix-Assisted Larer Desorp tion Ionization Time of Flight Mass Spectrometry(MALDI-TOF-MS). The molecular weightof bovine brain CaM, 16 699. 9 Da determined by MALDI-TOF-MS, is closely ideatical with16 700 Da, calculated from its primary sequence, showing the high accuracy of MALDITOF-MS and the conf1rmation of previously determined sequence. Furthermore, the molecular weight of intracellular CaM and extracellular CaM determined by MAlDI-TOF-MS, 17025 Da and 15 582 Da, are in agreement with 17 500 Da and 15 000 Da determined by SDSPAGE-This agreement shows the high accuracy of MALDI-TOF-MS. In addition, themolecular weight of CaMs with this technique can be determined rapidly(less than 10 min)and sensitively.