KCS

We characterized the small proteins of insulin (51 amino acids, 5,733 Da) using FRIPS (free radical initiated peptide sequencing) mass spectrometry. Insulin consists of two segments, A-chain and B-chain, which are linked together by a multiple disulfide bonds, TEMPO-assisted FRIPS MS approach is reported to selectively cleave the disulfide bond. However, it is not reported yet whether or not it is applicable for peptides/proteins with multiple disulfide bonds. In the present study, we applied the TEMPO-assisted FRIPS approach to the insulin to see how multiple disulfide bonds affects the fragmentation behavior of peptides with multiple disulfide bonds. In our preliminary results, it was found that with TEMPO-assisted FRIPS can provide more detailed structural information of insulin without the reduction of disulfide bonds than the conventional CID could do. In the symposium, we will discuss the potential use future direction of the current research.