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GC‐MS analysis of aldehydes reveals diverse pathways of lipid hydroperoxide metabolism with myoglobin
Author(s) -
Quintus Elizabeth S.,
Basu Hemendra,
Nethi Mallika,
Dave Nimita D.,
Holmes Heather L.S.,
Pernecky Steven J.
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.5.lb44-d
Subject(s) - chemistry , myoglobin , hexanal , metmyoglobin , aldehyde , metabolite , lipid oxidation , tbars , biochemistry , malondialdehyde , chromatography , lipid peroxidation , organic chemistry , enzyme , catalysis , antioxidant
A comprehensive profile of aldehyde production is being developed as a tool to probe the factors that influence lipid hydroperoxide reactions by hemeproteins. Cryofocusing coupled with GC‐TOFMS provided a real‐time method for monitoring the volatile metabolite hexanal, and formation of pentafluoro benzyl oxime or pentafluro phenyl hydrazine derivatives and GC analysis were used to monitor malondialdehyde (MDA) and 4hydroxynonenal (4HNE) production. Studies with equine metmyoglobin (metMb) indicate that hydroperoxides in arachidonic acid (AA) are required for MDA and 4HNE production, that the molar ratio of MDA to 4HNE formed is greater for AA than for AA in phospholipid, and that trace metals in the metMb preparations contributed to some extent to the formation of MDA and 4HNE. The results suggest that the form of AA presented to metMb influences disposition of lipid hydroperoxides. Treatment of metMb with H 2 O 2 forms a protein‐bound heme adduct (MbH). MbH is more effective than Mb at generating TBARS products with phospholipids containing AA, although much less capable of forming MDA, 4HNE, and hexanal. MbH has optimal activity at low ionic strength (0.2 mM NaOAc, pH 6 or 7), whereas Mb has optimal activity at 2 mM NaOAc, pH 5. MbH is very active at supporting formation of lipid hydroperoxides, but does not influence as extensively as does metMb their conversion to aldehydes. Supported by NSF grant 9987063.