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Sequencing peptides by electrospray ion-trap mass spectrometry: A useful tool in synthesis of Axinastatin 3

100%

Jia C., Qi W., He Z., Qiao B.

Open Chemistry

2006

vol. 4

issue 4

620-631

Axinastatin 3 as a potential anticancer agent was synthesized by chemical methods. In an electrospray ion-trap mass spectrometer, using one stage of tandem mass spectrometry (MS/MS), the linear peptide intermediate was sequenced via the complementarities of y and b ions. Then, using multistep MS/MS (to MS6), the cyclic peptide was sequenced through sequentially removing one amino acid residue in each stage of MS/MS. The difference of the fragmentation mechanisms and the sequencing approaches between them is discussed.

Synthesis of heptapeptides and analysis of sequence by tandem ion trap mass spectrometry

88%

Jia C., Qi W., He Z., Yang H., Qiao B.

Open Chemistry

2006

vol. 4

issue 2

285-298

Two heptapeptides have been prepared by Fmoc methodology using Wang resin as solid support. For attachment of the first amino acid, several coupling systems were evaluated, and DIC/DMAP system could give yields of >99% and low levels of racemization. The selection of scavenger combination to deprotect side chains revealed that H2O/p-cresol was good at scavenging trityl and 1,2-ethanedithiol was highly efficient for scavenging t-butyl. Through shortening the preactivation time to 5 min, the racemization which occurred during formation of amide bonds coupled by HBTU was minimized. The crude peptides were characterized by RP-HPLC and MS, and sequenced by MS/MS to acquire reliable amino acid sequence information.

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2 Open Chemistry

2 2006

2 He Z.

2 Jia C.

2 Qi W.

2 Qiao B.

1 Yang H.

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Sequencing peptides by electrospray ion-trap mass spectrometry: A useful tool in synthesis of Axinastatin 3

Synthesis of heptapeptides and analysis of sequence by tandem ion trap mass spectrometry