AcetylCoA

FIGURE 5. Assay for Met(0)-peptide reductase. The assay for Met(OJ-peptide reductase is carried out in a two-step incubation. The first incubation mixture contains Met(OJ-L12, DTT and the Met(OJ-peptide reductase. At the end of this incubation, purified L12 transacetylase and [3H]acetylCoA are added and the amount of radioactivity incorporated into L7 is determined by its ability to be retained on a nitrocellulose filter. The latter represents the amount of Met(0)-L12 reduced since the oxidized protein is not a substrate for the transacetylase. 

The main metabohtes produced by Monascus are polyketides formed by the condensation of one acetylcoA with one or more malonylcoAs with a simultaneous decarboxylation as in the case of lipidic synthesis. They consist of the pigments, monacohns, and under certain conditions a mycotoxin. 

Three of the eight Ni proteins that are known as hydrogenase, CO dehydrogenase (CODH), and acetylCoA synthase (ACS), are Ni-Fe-S proteins. Hydrogenases play an important role in microbial energy metabolism by catalysing the reversible oxidation of hydrogen ... 

Figure 15.6 The Wood-Ljungdahl pathway. One molecule of C02 (blue) is converted to formate and then reduced to a methyl group, which is then transferred to the corrinoid-iron-sulphur protein CFeSP. CFeSP transfers the methyl group to the A-cluster of the bifunctional CODH/ACS. The other molecule of C02 (red) is reduced to CO by the C-cluster of the CODH subunit. The CO is then transferred to the A-cluster through a long channel, some 70 A long, where with the methyl group and CoA it forms acetylCoA. (From Drennan et al., 2004. With kind permission of Springer Science and Business Media.)...

FIGURE 2.5 Cholinergic synapse. Acetylcholine hinds to muscarinic receptors (1) and nicotinic receptors (2). Acetylcholinesterase (AchE) cleaves the neurotransmitter acetylcholine into acetylCoA and choline. 

Acetylcholine is removed from the synapse through hydrolysis into acetylCoA and choline by the enzyme acetylcholinesterase (AChE). Removing ACh from the synapse can be blocked irreversibly by organophosphorous compounds and in a reversible fashion by drugs such as physostigmine. 

These enzymes convert acetylCoA thioesters into -a,/S-enoyl-CoA products. The presence of radicals in this reaction has been investigated in one example by using spiropentylacetyl-CoA as a probe giving the radicals 72-74 (Scheme 4). ... 

AcetylCoA carboxylase Glycogen synthase HMGCoA reductase NO synthase Biosynthesis of fatty adds Glycogen synthesis Biosynthesis of cholesterol Biosynthesis of NO ... 

Amino acids that give rise to ketone bodies (acetylCoA or acetoacetyl-CoA, neither of which can bring about net glucose production) are called ketogenic amino acids. Leucine and lysine are ketogenic amino acids. Some amino acids, e.g. threonine, isoleucine, phenylalanine, tyrosine and tryptophan, can be both ketogenic and glycogenic. 

AcetylCoA-solution 5.0 mg acetylcoenzyme A (Sigma) is dissolved in 1.008 ml demineralized water to yield a 6-mM solution that should be prepared immediately before the assay is run. 

Figure 1.35 Schematic diagram of the phenolic biosynthetic pathway accompanied by the key enzymes involved. Enzyme abbreviations PAL, phenylalanine ammonia-lyase BA2H, benzoic acid 2-hydroxylase C4H, cinnamate 4-hydroxylase COMT-1, caffeic/5-hydroxyferulic acid O-methy I transferase 4CL, p-co um a ra te C o A ligase F5H, ferulate 5-hydroxylase GT, galloyltransferase ACoAC, acetylCoA carboxylase.

Carbon monoxide dehydrogenase-acetylCoA synthase, models, 8, 124... 

NAD0X + formate + HzO = NADred + C02tot NAD0X + malate + H20 = NADred + C02tot + pyruvate NAD0X + ethanol = NADred + acetaldehyde NAD0X + alanine + H20 = NADred + pyruvate + ammonia NADox + malate + acetylcoA 4- H20 = NADrcd + citrate + coA (See Problem 9.5.) [With permission from R. A. Alberty, Arch. Biochem. Biophys. 389, 94-109 (2001). Copyright Academic Press.]... 

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