(methionine synthase) reductase

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In enzymology, a [methionine synthase] reductase (EC is an enzyme that catalyzes the chemical reaction

2 [methionine synthase]-methylcob(I)alamin + 2 S-adenosylhomocysteine + NADP+ 2 [methionine synthase]-cob(I)alamin + NADPH + H+ + 2 S-adenosyl-L-methionine

The 3 substrates of this enzyme are [[[methionine synthase]-methylcob(I)alamin]], S-adenosylhomocysteine, and NADP+, whereas its 4 products are [[[methionine synthase]-cob(I)alamin]], NADPH, H+, and S-adenosyl-L-methionine.

This enzyme belongs to the family of oxidoreductases, specifically those oxidizing metal ion with NAD+ or NADP+ as acceptor. The systematic name of this enzyme class is [methionine synthase]-methylcob(I)alamin,S-adenosylhomocysteine:NADP+ oxidoreductase. Other names in common use include methionine synthase cob(II)alamin reductase (methylating), methionine synthase reductase, [methionine synthase]-cobalamin methyltransferase (cob(II)alamin, and reducing). It employs one cofactor, flavoprotein.


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  • Rommens JM, Scherer SW, Rosenblatt DS, Gravel RA (1998). "Cloning and mapping of a cDNA for methionine synthase reductase, a flavoprotein defective in patients with homocystinuria". Proc. Natl. Acad. Sci. U. S. A. 95: 3059&ndash, 64. PMID 9501215.
  • Olteanu H, Banerjee R (2001). "Human methionine synthase reductase, a soluble P-450 reductase-like dual flavoprotein, is sufficient for NADPH-dependent methionine synthase activation". J. Biol. Chem. 276: 35558&ndash, 63. PMID 11466310.
  • Olteanu H, Munson T, Banerjee R (2002). "Differences in the efficiency of reductive activation of methionine synthase and exogenous electron acceptors between the common polymorphic variants of human methionine synthase reductase". Biochemistry. 41: 13378&ndash, 85. PMID 12416982.

External links

The CAS registry number for this enzyme class is 207004-87-3.

Gene Ontology (GO) codes