Differences in Lysine Adduction by Acrolein and Methyl Vinyl Ketone: Implications for Cytotoxicity in Cultured Hepatocytes
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- 作者：Lisa M. Kaminskas ; Simon M. Pyke ; and Philip C. Burcham
- 刊名：Chemical Research in Toxicology
- 出版年：2005
- 出版时间：November 2005
- 年：2005
- 卷：18
- 期：11
- 页码：1627 - 1633
- 全文大小：191K
- 年卷期：v.18,no.11(November 2005)
- ISSN：1520-5010
文摘
Acrolein is a highly toxic environmental pollutant that readily alkylates the 
-amino group oflysine residues in proteins. In model systems, such chemistry involves sequential addition oftwo acrolein molecules to a given nitrogen, forming bis-Michael-adducted species that undergoaldol condensation and dehydration to form N-(3-formyl-3,4-dehydropiperidino)lysine. Whetherthis ability to form cyclic adducts participates in the toxicity of acrolein is unknown. To addressthis issue, we compared the chemistry of protein adduction by acrolein to that of its close structuralanalogue methyl vinyl ketone, expecting that the 
-methyl group would hinder the intramolecularcyclization of any bis-adducted species formed by methyl vinyl ketone. Both acrolein and methylvinyl ketone displayed comparable protein carbonylating activity during in vitro studies withthe model protein bovine serum albumin, confirming the ,
,-unsaturated bond of both compoundsis an efficient Michael acceptor for protein nucleophiles. However, differences in adductionchemistry became apparent during the use of electrospray ionization-MS to monitor reactionproducts in a lysine-containing peptide after modification by each compound. For example,although a Schiff base adduct was detected following reaction of the peptide with acrolein, ananalogous species was not formed by methyl vinyl ketone. Furthermore, while ions correspondingto mono- and bis-Michael adducts were detected at the N-terminus and lysine residues followingpeptide modification by both carbonyls, only acrolein modification generated ions attributable tocyclic adducts. Despite these differences in adduction chemistry, in mouse hepatocytes, the twocompounds exhibited very comparable abilities to induce rapid, concentration-dependent cell deathas well as protein carbonylation. These findings suggest that the acute toxicity of short-chain,-unsaturated carbonyl compounds involves their ability to form acyclic Michael addition adductsrather than Schiff conjugates or heterocyclic adducts.
-amino group oflysine residues in proteins. In model systems, such chemistry involves sequential addition oftwo acrolein molecules to a given nitrogen, forming bis-Michael-adducted species that undergoaldol condensation and dehydration to form N-(3-formyl-3,4-dehydropiperidino)lysine. Whetherthis ability to form cyclic adducts participates in the toxicity of acrolein is unknown. To addressthis issue, we compared the chemistry of protein adduction by acrolein to that of its close structuralanalogue methyl vinyl ketone, expecting that the -methyl group would hinder the intramolecularcyclization of any bis-adducted species formed by methyl vinyl ketone. Both acrolein and methylvinyl ketone displayed comparable protein carbonylating activity during in vitro studies withthe model protein bovine serum albumin, confirming the ,,-unsaturated bond of both compoundsis an efficient Michael acceptor for protein nucleophiles. However, differences in adductionchemistry became apparent during the use of electrospray ionization-MS to monitor reactionproducts in a lysine-containing peptide after modification by each compound. For example,although a Schiff base adduct was detected following reaction of the peptide with acrolein, ananalogous species was not formed by methyl vinyl ketone. Furthermore, while ions correspondingto mono- and bis-Michael adducts were detected at the N-terminus and lysine residues followingpeptide modification by both carbonyls, only acrolein modification generated ions attributable tocyclic adducts. Despite these differences in adduction chemistry, in mouse hepatocytes, the twocompounds exhibited very comparable abilities to induce rapid, concentration-dependent cell deathas well as protein carbonylation. These findings suggest that the acute toxicity of short-chain,-unsaturated carbonyl compounds involves their ability to form acyclic Michael addition adductsrather than Schiff conjugates or heterocyclic adducts.