Flavin adenine dinucleotide oxidized

FAD flavin adenine dinucleotide (oxidized form) Km Michaelis constant... 

FAD flavin adenine dinucleotide (oxidized form) FADH2 flavin adenine dinucleotide (reduced form) fMet formylmethionine FMN flavin mononucleotide (oxidized form) FMNH2 flavin mononucleotide (reduced form)... 

BMR Basal metabolic rate FAD Flavin adenine dinucleotide (oxidized)... 

Nicotinamide adenine dinucleotide, oxidation-reduction flavin adenine dinucleotide, oxidation-reduction coenzyme A, acyl transfer pyridoxal phosphate, transamination biotin, carboxylation lipoic acid, acyl transfer. 

Among the spectra of coenzymes given by Rosenkrantz were glutathione (reduced and oxidized), diphosphopyridine nucleotide (DPN or NAD ) and its reduced form (Na salt), triphosphopyridine nucleotide and its reduced form (Na salt), flavin mononucleotide, flavin adenine dinucleotide, oxidized cytochrome c (containing some of the reduced form), and thiamine pyrophosphate. 

Flavin-adenine dinucleotide (oxidized and reduced) FAD, FADHj... 

This thiol-disulfide interconversion is a key part of numerous biological processes. WeTJ see in Chapter 26, for instance, that disulfide formation is involved in defining the structure and three-dimensional conformations of proteins, where disulfide "bridges" often form cross-links between q steine amino acid units in the protein chains. Disulfide formation is also involved in the process by which cells protect themselves from oxidative degradation. A cellular component called glutathione removes potentially harmful oxidants and is itself oxidized to glutathione disulfide in the process. Reduction back to the thiol requires the coenzyme flavin adenine dinucleotide (reduced), abbreviated FADH2. 

Step 1 of Figure 29.3 Introduction of a Double Bond The /3-oxidation pathway begins when a fait)7 acid forms a thioester with coenzyme A to give a fatty acyl Co A. Two hydrogen atoms are then removed from C2 and C3 of the fatty acyl CoA by one of a family of acyl-CoA dehydrogenases to yield an a,/3-unsaturated acyl CoA. This kind of oxidation—the introduction of a conjugated double bond into a carbonyl compound—occurs frequently jn biochemical pathways and usually involves the coenzyme flavin adenine dinucleotide (FAD). Reduced FADH2 is the by-product. 

Flavin Adenine Dinucleotide (FAD) (C27 H33 N9 O15P2) is a coenzyme that acts as a hydrogen acceptor in dehydrogenation reactions in an oxidized or reduced form. FAD is one of the primary cofactors in biological redox reactions. 

Figure 17-5. Oxidative decarboxylation of pyruvate by the pyruvate dehydrogenase complex. Lipoic acid is joined by an amide link to a lysine residue of the transacetylase component of the enzyme complex. It forms a long flexible arm, allowing the lipoic acid prosthetic group to rotate sequentially between the active sites of each of the enzymes of the complex. (NAD nicotinamide adenine dinucleotide FAD, flavin adenine dinucleotide TDP, thiamin diphosphate.)...

Walsh and coworkers oxidized ethyl p-tolyl sulfide on an analytical scale to the S-sulfoxide of 64% enantiomeric purity using a bacterial flavoenzyme cyclohexanone monooxygenase derived from Adnetobacter . Using a flavin adenine dinucleotide containing monooxygenase purified from hog liver microsomes yielded the R-sulfoxide of 90% enantiomeric purity. HPLC on a column containing a 3,5-dinitrobenzoyl-D-phenylglycine chiral stationary phase was used to determine the optical purity of the sulfoxides. 

XOD is one of the most complex flavoproteins and is composed of two identical and catalytically independent subunits each subunit contains one molybdenium center, two iron sulfur centers, and flavine adenine dinucleotide. The enzyme activity is due to a complicated interaction of FAD, molybdenium, iron, and labile sulfur moieties at or near the active site [260], It can be used to detect xanthine and hypoxanthine by immobilizing xanthine oxidase on a glassy carbon paste electrode [261], The elements are based on the chronoamperometric monitoring of the current that occurs due to the oxidation of the hydrogen peroxide which liberates during the enzymatic reaction. The biosensor showed linear dependence in the concentration range between 5.0 X 10 7 and 4.0 X 10-5M for xanthine and 2.0 X 10 5 and 8.0 X 10 5M for hypoxanthine, respectively. The detection limit values were estimated as 1.0 X 10 7 M for xanthine and 5.3 X 10-6M for hypoxanthine, respectively. Li used DNA to embed xanthine oxidase and obtained the electrochemical response of FAD and molybdenum center of xanthine oxidase [262], Moreover, the enzyme keeps its native catalytic activity to hypoxanthine in the DNA film. So the biosensor for hypoxanthine can be based on... 

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