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- ***************************************************************
- * FMN-dependent alpha-hydroxy acid dehydrogenases active site *
- ***************************************************************
-
- A number of oxidoreductases that act on alpha-hydroxy acids and which are
- FMN-containing flavoproteins have been shown [1,2,3] to be structurally
- related; these enzymes are:
-
- - Lactate dehydrogenase (EC 1.1.2.3), which consists of a dehydrogenase
- domain and a heme-binding domain called cytochrome b2 and which catalyzes
- the conversion of lactate into pyruvate.
- - Glycolate oxidase (EC 1.1.3.15) ((S)-2-hydroxy-acid oxidase), a peroxisomal
- enzyme that catalyzes the conversion of glycolate and oxygen to glyoxylate
- and hydrogen peroxide.
- - Long chain alpha-hydroxy acid oxidase from rat (EC 1.1.3.-), a peroxisomal
- enzyme.
- - Lactate 2-monooxygenase (EC 1.13.12.4) (lactate oxidase) from Mycobacterium
- smegmatis, which catalyzes the conversion of lactate and oxygen to acetate,
- carbon dioxide and water.
- - (S)-mandelate dehydrogenase from Pseudomonas putida (gene mdlB), which
- catalyzes the reduction of (S)-mandelate to benzoylformate.
-
- The first step in the reaction mechanism of these enzymes is the abstraction
- of the proton from the alpha-carbon of the substrate producing a carbanion
- which can subsequently attach to the N5 atom of FMN. A conserved histidine
- has been shown [4] to be involved in the removal of the proton. The region
- around this active site residue is highly conserved and contains an arginine
- residue which is involved in substrate binding.
-
- -Consensus pattern: S-N-H-G-[AG]-R-Q
- [H is the active site residue]
- [R is a substrate-binding residue]
- -Sequences known to belong to this class detected by the pattern: ALL.
- -Other sequence(s) detected in SWISS-PROT: NONE.
- -Last update: December 1991 / First entry.
-
- [ 1] Giegel D.A., Williams C.H. Jr., Massey V.
- J. Biol. Chem. 265:6626-6632(1990).
- [ 2] Tsou A.Y., Ransom S.C., Gerlt J.A., Buechter D.D., Babbitt P.C.,
- Kenyon G.L.
- Biochemistry 29:9856-9862(1990).
- [ 3] Diep Le K.H., Lederer F.
- J. Biol. Chem. 266:20877-20880(1991).
- [ 4] Lindqvist Y., Branden C.-I.
- J. Biol. Chem. 264:3624-3628(1989).
-