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The Study of a Catalytic Intermediate of Methylenetetrahydrofolate Reductase
Author(s) -
De la Rosa Metzere Bierlein,
Trimmer Elizabeth
Publication year - 2012
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.26.1_supplement.756.14
Subject(s) - methylenetetrahydrofolate reductase , chemistry , reductase , enzyme , flavoprotein , stereochemistry , biochemistry , biosynthesis , methionine , substrate (aquarium) , cofactor , biology , amino acid , gene , allele , ecology
The flavoprotein Methylenetetrahydrofolate reductase (MTHFR) is an essential enzyme in the methionine biosynthesis pathway. It catalyzes the reduction of 5,10 methylenetetrahydrofolate (CH 2 ‐H 4 folate) to 5‐methyltetrahydrofolate (CH 3 ‐H 4 folate), which acts as a methyl donor to homocysteine to form methionine. It has recently been discovered that there is at least one, uncharacterized intermediate in the folate oxidative half‐reaction of MTHFR. Stopped‐flow experiments show the formation of a species at 337 nm which is decayed by one second. We believe this intermediate to represent either an E red *5‐iminium cation complex or an E red * CH 2 ‐H 4 folate complex in which either enzyme or substrate has undergone a conformational change. We have gathered preliminary data on the putative intermediate by performing a series of anaerobic titrations with the enzyme and a variety of substrates. Additionally, two folates have been characterized by fluorescence in the absence and presence of enzyme. We are currently gathering quench‐flow samples in an attempt to analyze the intermediate by LC‐MS. Research was supported by HHMI grant #52006298 to Grinnell College.