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Mannitol prevents methionine sulphoxidation mediated electrophoretic heterogeneity of apolipoprotein A‐I
Author(s) -
Nofer JerzyRoch,
von Eckardstein Arnold,
Assmann Gerd
Publication year - 1995
Publication title -
biomedical chromatography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.4
H-Index - 65
eISSN - 1099-0801
pISSN - 0269-3879
DOI - 10.1002/bmc.1130090106
Subject(s) - isoelectric focusing , chemistry , methionine , apolipoprotein b , mannitol , isoelectric point , chromatography , biochemistry , amino acid , enzyme , cholesterol
Hybrid isoelectic focusing of apolipoprotein A‐I in polyacrylanide gels with immobilized pH‐gradients under non‐denaturing conditions resulted in the occurrence of additional bands which could prevent the specific and sensitive detection of genetic variants. Hybrid isoelectric focusing of tow chromatographically distinguishable apolipoprotien A‐I isoforms that differ by sulphoxidaton of methionine residues, apo A‐I(Met) and apo A‐I(MetSO), revealed that the additional bands were caused by this post‐translational modification. Several antioxidative additives and conditions were compared for their ability to prevent methionine sulphoxidation in apoliporotein A‐I In the presence of 200 g/L mannitol in the gel, apolipoprotein A/I focused as a single band. Since methionine sulphoxidation in proteins is a general phenomenon either taking place in vivo or in vitro by isoelectric focusing, we conclude that isoelectric focusing in the presence of mannitol will improve the quality of resolution of many proteins in gels with immobilized pH‐gradients.