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Hydratases hydratase/dehydratase

Lyases. These enzymes cleave C-C, C-0, C-N and other bonds by elimination leaving double bonds or conversely add groups to double bonds. This group includes decarboxylases, hydratases, dehydratases and some carboxylases. [Pg.159]

Class 4. Lyases split a molecule by a nonhydrolytic process, leaving double bonds (or alternatively, by adding groups to double bonds). They include decarboxylases, aldolases, hydratases, dehydratases, and synthases (synthetic enzymes). [Pg.88]

Lyases Decarboxylases Aldolases Hydratases Dehydratases Removal of groups by a mechanism other than hydrolysis leaving a double bond in one of the product. A - H-+A-H. +. X-V X V... [Pg.183]

Lyases Catalyze the nonhydrolytic removal of groups Decarboxylases, aldolases, ketolases, hydratases, dehydratases... [Pg.105]

Lyases. Lyases catalyze reactions in which groups (e.g., H20, COz, andNH3) are removed to form a double bond or are added to a double bond. Decarboxylases, hydratases, dehydratases, deaminases, and synthases are examples of lyases. [Pg.168]

While Fe(SCys)4, [2Fe-2S], [3Fe-4S] and [4Fe-4S] clusters all function as one-electron donors or acceptors, the more complex double-cubane [8Fe-7S] cluster that is found only in nitrogenases (see Nitrogenase Catalysis Assembly) has the potential to mediate two-electron transfer processes.Three methods have been employed to functionalize Fe-S centers for substrate binding and activation. The first involves having an accessible Fe coordination site as in the mononuclear Fe centers of nitrile hydratase and SOR, and the [4Fe-4S] clusters at the active sites of hydratases/dehydratases and radical-5-adenosylmethionine (SAM) enzymes.Indeed the recent recognition of the importance of the superfamily of radical-SAM enzymes in initiating radical reactions, via cluster-mediated reductive cleavage of SAM to yield a... [Pg.2300]

In industrial processes, 1,3-propanediol is used for the production of polyester fibers, polyurethanes and cydic compounds [85]. 1,3-Propanediol can be produced from glucose with the limiting step catalyzed by glycerol dehydratase. A metagenomic survey for glycerol hydratases from the environment resulted in seven positive clones, one of which displayed a level of catalytic efficiency and stability making it ideal for application in the produdion of 1,3-propanediol from glucose. [Pg.79]

The discovery and exploitation of enzymes in aldoxime-nitrile pathway nitrile hydratase, amidase, nitrilase, aldoxime dehydratase, etc., are shown along with the use of methodologies, such as organic chemistry, microbial screening by enrichment and acclimation culture techniques, enzyme purification, gene cloning, molecular screening by polymerase chain reaction (PCR). [Pg.129]

We also found that the occurrence of aldoxime dehydratase is as wide as that for nitrile-degrading enzymes such as nitrile hydratase, amidase and/or nitri-lase. All of the nitrile degraders hitherto isolated contained aldoxime dehydratase activities. The author would like to propose that the pathway in which aldoximes are successively degraded via nitrile could be named as the aldoxime-nitrile pathway (Fig. 1). [Pg.135]

Carbonate dehydratase [Zn " ]— carbonic anhydrase Fumarate hydratase— fumarase ... [Pg.428]

Serine dehydratase Enoyl-CoA hydratase Methylglutaconyl-CoA hydratase Cystathionine p-synthase [PLP]... [Pg.428]

Porphobilinogen synthase Urocanate hydratase 3-Hydroxypalmitoyl-[ACP] dehydratase Uroporphyrinogen 111 synthase... [Pg.428]

Lyases Decarboxylases Dehydratases Hydratases Add the elements of water, ammonia, or carbon dioxide across a double bond (or the reverse reaction)... [Pg.26]

Other enzymes in the aconitase family include isopropylmalate isomerase and homoaconitase enzymes functioning in the chain elongation pathways to leucine and lysine, both of which are pictured in Fig. 17-18.90 There are also iron-sulfur dehydratases, some of which may function by a mechanism similar to that of aconitase. Among these are the two fumarate hydratases, fumarases A and B, which are formed in place of fumarase C by cells of E. coli growing anaerobically.9192 Also related may be bacterial L-serine and L-threonine dehydratases. These function without the coenzyme pyridoxal phosphate (Chapter 14) but contain iron-sulfur centers.93-95 A lactyl-CoA... [Pg.689]

Aconitase is the trivial name for citrate dehydratase cw-aconitate hydratase (EC 4.2.1.3). It catalyzes the reversible isomerization reaction of citrate into isocitrate via the intermediate cA-aconitate (Figure 2). It is a water-soluble, monomeric protein. In eukaryotic cells aconitase is located in the mitochondrial matrix. In prokaryotes the enzyme occurs in the cytoplasma. The pig heart enzyme consists of 754 amino-acid residues, providing a molecular mass of 83 kDa [27], Aconitase from other sources has similar size. The porcine protein is synthesized with a mitochondrial targeting sequence. The mature, functional protein can be (over)expressed in Escherichia coli [28],... [Pg.214]

The addition of water to carbon-carbon double bonds is a reaction that is catalyzed by lyases belonging to the subclass of the hydro-lyases (E.C. 4.2.1.-), which have been grouped under the carbon-oxygen lyases. Not all members of this subgroup are capable of water addition to carbon-carbon double bonds. Nitrile hydratase (E. C. 4.2.1.84, discussed in Section 12.1) for instance, is categorized in this subclass and catalyzes the addition of water to nitriles. The nomenclature of the hydro-lyases subgroup, which contains hydratases and dehydratases, does not preclude any direction of the reaction, but rather reflects the context in which the enzyme was originally discovered. [Pg.686]

Other C-0 lyase enzymes include aconitate hydratase or aconitase (E. C. 4.2.1.3), an enzyme that catalyzes two tricarboxylic acid cycle steps from isocitric acid to citrate (14)1141 or vice versa, via the intermediate cis-aconitate (13). Citrate dehydratase (E. C. 4.2.1.4) is only capable of converting citrate to cis-aconitate and does not act on isocitrate (15) 115l... [Pg.688]

A similar reaction is catalyzed by homoaconitate hydratase (E.C. 4.2.1.36), which is an enzyme from the L-lysine synthesis that forms homocitric acid (2-hydrox-ybutane-l,2,4-tricarboxylic acid, 17) from homo-ris-aconitate (16)The enzyme 2-methylcitrate dehydratase (E. C. 4.2.1.79) catalyzes the addition of water to (Z)-but-2-ene-l,2,3-tricarboxylic acid (18) to yield 2-methylcitric acid (2-hydroxybutane-... [Pg.689]

Despite the fact that numerous enzymes have been characterized that catalyze the addition of water to unsaturated fatty acids that are coupled to CoA or ACP, such as methylglucatonyl-CoA hydratase (E.C. 4.2.1.18), lactoyl-CoA dehydratase (E.C. 4.2.1.54), 3-hydroxybutyryl-CoA dehydratase (E.C. 4.2.1.55), itaconyl-CoA dehydratase (E. C. 4.2.1.56), isohexenylglutaconyl-CoA hydratase (E. C. 4.2.1.57), farnesyl-CoA dehydratase (E.C. 4.2.1.57), long-chain enoyl-CoA hydratase (E.C. 4.2.1.74), 3-hydroxydecanoyl-ACP dehydratase (E.C. 4.2.1.60) and 3-hydroxypalmitoyl-ACP dehydratase (E.C. 4.2.1.61), these enzymes are seldomly applied in organic synthesis. [Pg.696]

Unsaturated fatty acids can also be degraded by the 3-oxidation pathway. The FadB protein possesses cw-P-enoyl-CoA isomerase activity, which converts cis-3 double bonds to trans-2 (Fig. 8). A 2,4-dienoyl-CoA reductase encoded by fadH is also required for the metabolism of polyunsaturated fatty acids (Fig. 8). This protein is a 73-kDa monomeric, NADP" -dependent, 4Fe-4S flavoprotein. The FadH protein can utilize compounds with either cis or trans double bonds at the 4-position. An epimerase activity of FadB allows for the utilization of D-hydroxy fatty acids. The epimerase is actually a combination of a Z)-P-hydroxyacyl-CoA dehydratase and the crotonase (hydratase) activities, resulting in the conversion of the d to the L enantiomer (Fig. 8). [Pg.82]

Figure 7 Other dehydratases that may use a [4Fe-4S] cluster in an analogous manner to aconitase. A. Isopropylmalate isomerase. B. Fumarase. C. Dihydroxyacid dehydratase. D. Maleic acid hydratase. Figure 7 Other dehydratases that may use a [4Fe-4S] cluster in an analogous manner to aconitase. A. Isopropylmalate isomerase. B. Fumarase. C. Dihydroxyacid dehydratase. D. Maleic acid hydratase.
Dehydratases remove water, as in fumarase (fumarate hydratase) ... [Pg.93]

The second step of the P-oxidation spiral is the reversible hydration of 2-trans-enoyl-CoA to yield L-3-hydroxyacyl-CoA, catalyzed by enoyl-CoA hydratase. However, in fungi 2-tra 5-enoyl-CoA is hydrated by peroxisomal D-3-hydroxyacyl-CoA dehydratase to form D-3-hydroxyacyl-CoA. Enoyl-CoA hydratases are usually associated with the N-terminal region of multifunctional proteins except for the mitochondrial matrix enoyl-CoA hydratase and the E. coli long-chain enoyl-CoA hydratase (see Table 1). D-3-hydioxyacyl-CoA dehydratases are located on the C-terminal domain of the peroxisomal D-specific bifunctional P-oxidation enzyme or the central domain of 1 P-hydroxysteroid dehydrogenase type IV. ... [Pg.134]

The syn p-addition/elimination of water proved not to be superior to an anti process in chemical efficiency. The reason why the reaction catalyzed by enoyl-CoA hydratases follows the syn stereochemical course is because the two catalytic residues of the hydratase are located on the same side of the substrate (see Fig. 2). The reaction mechanism of D-3-hydroxyacyl-CoA dehydratase catalysis is not known. If it follows the anti stereochemical course, the D-specific dehydratases of the peroxisomal multifunctional... [Pg.135]

Jiang, L.L., Kobayashi, A., Matsuura, H., Fukushima, H. Hashimoto, T. (1996) J. Biochem. Tokyo 120, 624-632. Purification and properties of human D-3-hydroxyacyl-CoA dehydratase medium-chain enoyl-CoA hydratase is D-3-hydroxyacyl-CoA dehydratase. [Pg.271]


See other pages where Hydratases hydratase/dehydratase is mentioned: [Pg.428]    [Pg.211]    [Pg.211]    [Pg.2301]    [Pg.211]    [Pg.145]    [Pg.396]    [Pg.142]    [Pg.142]    [Pg.78]    [Pg.134]    [Pg.2316]    [Pg.688]    [Pg.688]    [Pg.690]    [Pg.694]    [Pg.231]    [Pg.258]    [Pg.260]    [Pg.30]    [Pg.2315]    [Pg.747]    [Pg.17]   
See also in sourсe #XX -- [ Pg.690 ]




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Hydratase

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