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  • 09월 04일 17시 이후 : 초록수정 불가능, 일정확인 및 검색만 가능

제114회 대한화학회 학술발표회, 총회 및 기기전시회 안내 Dimethylation vs. Acetylation in Electrospray Ionization Efficiency and Identification Integrity

2014년 9월 2일 10시 10분 17초
ANAL.P-581 이곳을 클릭하시면 발표코드에 대한 설명을 보실 수 있습니다.
10월 15일 (수요일) 16:00~19:00
저자 및
위영진, 김태우*, 김광표1,*
경희대학교 동서의학대학원, Korea
1경희대학교 응용화학과, Korea
Peptide acetylation has widely been used for blocking N-terminal amines and ε-amines of lysine residues in ESI MS. For example acetylation reactions of proteolytic peptides were applied to i) chemical isotope labeling for quantitative proteomics (e.g. Terminal amine isotope labeling of substrates, TAILS), and ii) affinity tag labeling for targeted proteomics (e.g. nitroprotein proteomics). However, peptide acetylation results in the serious reduction of peptide signals during ESI ionization. This phenomenon may be related with charge neutralization form amine (z = +1) to amide (z = 0) after acetylation in a common ESI condition (e.g. 0.1 % formic acid). To overcome the signal reduction problem due to acetylation, we introduced dimethylation reaction to block amino groups on tryptic peptides keeping their positive charge after the blocking reaction. We quantitatively compared the electrospray ionization efficiency and identification integrity of dimethylation and acetylation in tryptic BSA and ischemia sample. Peptide dimethylation showed higher ESI RI (relative intensity) than peptide acetylation in tryptic BSA (up to 375 times enhancement). In addition peptide dimethylation reduced the bias of identification rate by chemical modification in ischemia sample (RID integrity = No peptides ending with Arg/No. peptides ending with Lys = 2.96 (?0.11), 0.75 (?0.05) for acetylated and dimethylated sample, cf. RID integrity = 1.01 (?0.04) for intact sample). These results suggest that dimethylation of tryptic peptides be a more efficient and less biased blocking method than acetylation for ESI-MS/MS.