Search results
Results From The WOW.Com Content Network
In biochemistry, flavin adenine dinucleotide (FAD) is a redox-active coenzyme associated with various proteins, which is involved with several enzymatic reactions in metabolism. A flavoprotein is a protein that contains a flavin group, which may be in the form of FAD or flavin mononucleotide (FMN).
The oxidized and reduced forms are in fast equilibrium with the semiquinone form, shifted against the formation of the radical: [2] Fl ox + Fl red H 2 ⇌ FlH • where Fl ox is the oxidized flavin, Fl red H 2 the reduced flavin (upon addition of two hydrogen atoms) and FlH • the semiquinone form (addition of one hydrogen atom).
The flavin is generally tightly bound (as in adrenodoxin reductase, wherein the FAD is buried deeply). [1] About 5-10% of flavoproteins have a covalently linked FAD. [ 2 ] Based on the available structural data, FAD-binding sites can be divided into more than 200 different types.
1 FADH 2 : 6 H + : 6/4 ATP = 1 FADH 2 : 1.5 ATP. ATP : NADH+H + coming from glycolysis ratio during the oxidative phosphorylation is 1.5, as for FADH 2, if hydrogen atoms (2H + +2e −) are transferred from cytosolic NADH+H + to mitochondrial FAD by the glycerol phosphate shuttle located in the inner mitochondrial membrane.
FAD is a unique electron acceptor. Its fully reduced form is FADH 2 (known as the hydroquinone form), but FAD can also be partially oxidized as FADH by either reducing FAD or oxidizing FADH 2. [11] Dehydrogenases typically fully reduce FAD to FADH 2. The production of FADH is rare.
The dihydrolipoate, covalently bound to a lysine residue of the complex, is then transferred to the Dihydrolipoyl dehydrogenase (E3) active site, [1] where it undergoes a flavin-mediated oxidation, similar in chemistry to e.g. thioredoxin reductase. First, FAD oxidizes dihydrolipoate back to its lipoate (disulfide) resting state, producing FADH 2.
d -Glucose + 2 [NAD] + + 2 [ADP] + 2 [P] i 2 × Pyruvate 2 × + 2 [NADH] + 2 H + + 2 [ATP] + 2 H 2 O Glycolysis pathway overview The use of symbols in this equation makes it appear unbalanced with respect to oxygen atoms, hydrogen atoms, and charges. Atom balance is maintained by the two phosphate (P i) groups: Each exists in the form of a hydrogen phosphate anion, dissociating to contribute ...
In enzymology, a FMN adenylyltransferase (EC 2.7.7.2) is an enzyme that catalyzes the chemical reaction. ATP + FMN diphosphate + FAD. Thus, the two substrates of this enzyme are ATP and FMN, whereas its two products are diphosphate and FAD.