Determination of first-order structure of somatostatin by electrospray ionization mass spectrometry
Zhou, H-hua.; Ma, R-ling.; Sheng, L-sheng.; Xiang, B-ren.; An, D-kui.
Yao Xue Xue Bao 38(8): 617-619
2003
ISSN/ISBN: 0513-4870 PMID: 14628455 Document Number: 554918
Aim: To determine the molecular weight and first-order structure of somatostatin. Methods: The molecular weight of somatostatin was determined by electrospray ionization mass spectrometry. Somatostatin was deoxidized by 2-mercaptoethanol. A series of typical fragment ions of deoxidized product were obtained by insource collision-induced dissociation (CID). Results: The m/z of quasi-molecular ion (M+H)+ of somatostatin was 1 637.8 and (M+Na)+ was 1 659.5. The m/z of double-charge ion (M+2H)2+ was 819.5 and (M+H+Na)2+ was 830.3. It showed that the molecular weight of somatostatin was 1 636.7. The y and b series of fragment ions of deoxidized product were obtained by adjusting the fragmentor voltage. It was determined that the first-order structure of deoxidized product of somatostatin was A-G-C-K-N-F-F-W-K-T-F-T-S-C. Conclusion: The molecular weight and first-order structure of somatostatin were confirmed.