title: [Determination of first-order structure of somatostatin by electrospray ionization mass spectrometry].
abstract: OBJECTIVE
  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.
  
  
  CONCLUSIONS
  The molecular weight and first-order structure of somatostatin were confirmed.
authors: Center for Instrumental Analysis, China Pharmaceutical University, Nanjing 210009, China. Honghua.zhou@sohu.com
authors: Hong-hua
authors: HH
authors: Zhou
authors: Ren-ling
authors: RL
authors: Ma
authors: Long-sheng
authors: LS
authors: Sheng
authors: Bing-ren
authors: BR
authors: Xiang
authors: Deng-kui
authors: DK
authors: An
mesh_terms: D000595:Amino Acid Sequence; D015394:Molecular Structure; D008970:Molecular Weight; D013004:Somatostatin / Q000032:analysis / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*
chemical_list: D013004:Somatostatin