Quinate dehydrogenase (quinone) (, NAD(P)+-independent quinate dehydrogenase, quinate:pyrroloquinoline-quinone 5-oxidoreductase) is an enzyme with systematic name quinate:quinol 3-oxidoreductase. This enzyme catalyses the following chemical reaction : quinate + quinone \rightleftharpoons 3-dehydroquinate + quinol This enzyme is membrane-bound.
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In enzymology, a quinate O-hydroxycinnamoyltransferase () is an enzyme that catalyzes the chemical reaction :feruloyl-CoA + quinate \rightleftharpoons CoA + O-feruloylquinate Thus, the two substrates of this enzyme are feruloyl-CoA and quinate, whereas its two products are CoA and O-feruloylquinate. This enzyme belongs to the family of transferases, specifically those acyltransferases transferring groups other than aminoacyl groups. The systematic name of this enzyme class is feruloyl-CoA:quinate O-(hydroxycinnamoyl)transferase. This enzyme is also called hydroxycinnamoyl coenzyme A-quinate transferase.
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Rice bran derived quinate merits further evaluation for similar antioxidant activities.
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3-Dehydroquinate goes through beta oxidation, similar to fatty acids. Then, this compound (6-oxo-3-dehydro-quinate) is transaminated to 6-amino-3-dehydroquinate. Then 6-amino-3-dehydro-quinate is dehydrated and reduced to 6-amino-4-desoxy-3-keto-quinate, which reacts with dehydroalanine and alpha-ketoglutarate, to form hexahydro-pyrroloquinoline quinone. This compound is oxidized by FAD to PQQ.
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In enzymology, a 5-O-(4-coumaroyl)-D-quinate 3'-monooxygenase () is an enzyme that catalyzes the chemical reaction :trans-5-O-(4-coumaroyl)-D-quinate + NADPH + H+ \+ O2 \rightleftharpoons trans-5-O-caffeoyl-D-quinate + NADP+ \+ H2O The 4 substrates of this enzyme are trans-5-O-(4-coumaroyl)-D-quinate, NADPH, H+, and O2, whereas its 3 products are trans-5-O-caffeoyl-D-quinate, NADP+, and H2O. This enzyme belongs to the family of oxidoreductases, specifically those acting on paired donors, with O2 as oxidant and incorporation or reduction of oxygen. The oxygen incorporated need not be derived from O2 with NADH or NADPH as one donor, and incorporation of one atom o oxygen into the other donor. The systematic name of this enzyme class is trans-5-O-(4-coumaroyl)-D-quinate,NADPH:oxygen oxidoreductase (3'-hydroxylating).
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In enzymology, a quinate dehydrogenase (pyrroloquinoline-quinone) () is an enzyme that catalyzes the chemical reaction :quinate + pyrroloquinoline- quinone \rightleftharpoons 3-dehydroquinate + reduced pyrroloquinoline-quinone Thus, the two substrates of this enzyme are quinate and pyrroloquinoline quinone, whereas its two products are 3-dehydroquinate and reduced pyrroloquinoline-quinone. This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-OH group of donor with other acceptors. The systematic name of this enzyme class is quinate:pyrroloquinoline-quinone 3-oxidoreductase. Other names in common use include NAD(P)+-independent quinate dehydrogenase, and quinate:pyrroloquinoline-quinone 5-oxidoreductase.
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In enzymology, a quinate dehydrogenase () is an enzyme that catalyzes the chemical reaction :L-quinate + NAD+ \rightleftharpoons 3-dehydroquinate + NADH + H+ Thus, the two substrates of this enzyme are L-quinate and NAD+, whereas its 3 products are 3-dehydroquinate, NADH, and H+. This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-OH group of donor with NAD+ or NADP+ as acceptor. The systematic name of this enzyme class is L-quinate:NAD+ 3-oxidoreductase. Other names in common use include quinic dehydrogenase, quinate:NAD oxidoreductase, quinate 5-dehydrogenase, and quinate:NAD+ 5-oxidoreductase. This enzyme participates in phenylalanine, tyrosine and tryptophan biosynthesis.
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The gene qa-3 which encoded quinate 5-dehydrogenase from Neurospora crassa wasn't expressed in Escherichia coli.
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Quinate/shikimate dehydrogenase (, YdiB) is an enzyme with systematic name L-quinate:NAD(P)+ 3-oxidoreductase. This enzyme catalyses the following chemical reaction : (1) L-quinate + NAD(P)+ \rightleftharpoons 3-dehydroquinate + NAD(P)H + H+ : (2) shikimate + NAD(P)+ \rightleftharpoons 3-dehydroshikimate + NAD(P)H + H+ This is the second shikimate dehydrogenase enzyme found in Escherichia coli and differs from EC 1.1.1.25, shikimate dehydrogenase, in that it can use both quinate and shikimate as substrate, and either NAD+ or NADP+ as acceptor.
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They are termed Binate, Ternate, or Quinate, growing two, three, or five together, according to the number of Folioles, of which the digitate Leaf consists.
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They are termed Binate, Ternate, or Quinate, growing two, three, or five together, according to the number of Folioles, of which the digitate Leaf consists.
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Other names in common use include 5-O-(4-coumaroyl)-D-quinate/shikimate 3'-hydroxylase, and coumaroylquinate(coumaroylshikimate) 3'-monooxygenase. This enzyme participates in phenylpropanoid biosynthesis.
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In enzymology, a chlorogenate hydrolase () is an enzyme that catalyzes the chemical reaction :chlorogenate + H2O \rightleftharpoons caffeate + quinate Thus, the two substrates of this enzyme are chlorogenate and H2O, whereas its two products are caffeate and quinate. This enzyme belongs to the family of hydrolases, specifically those acting on carboxylic ester bonds. The systematic name of this enzyme class is chlorogenate hydrolase. Other names in common use include chlorogenase, and chlorogenic acid esterase.
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In enzymology, a chlorogenate-glucarate O-hydroxycinnamoyltransferase () is an enzyme that catalyzes the chemical reaction :chlorogenate + glucarate \rightleftharpoons quinate + 2-O-caffeoylglucarate Thus, the two substrates of this enzyme are chlorogenate and glucarate, whereas its two products are quinate and 2-O-caffeoylglucarate. This enzyme belongs to the family of transferases, specifically those acyltransferases transferring groups other than aminoacyl groups. The systematic name of this enzyme class is chlorogenate:glucarate O-(hydroxycinnamoyl)transferase. Other names in common use include chlorogenate:glucarate caffeoyltransferase, chlorogenic acid:glucaric acid O-caffeoyltransferase, and chlorogenate:glucarate caffeoyltransferase.
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Type II is present in the quinate pathway of fungi and the shikimate pathway of most bacteria. It catalyzes a trans-dehydration using an enolate intermediate. It is heat stable and has Km values one or two orders of magnitude higher than the Type I Km values. The best studied type I enzyme is from Escherichia coli (gene aroD) and related bacteria.
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DAHP is then transformed to 3-dehydroquinate (DHQ), in a reaction catalyzed by DHQ synthase. Although this reaction requires nicotinamide adenine dinucleotide (NAD) as a cofactor, the enzymic mechanism regenerates it, resulting in the net use of no NAD. :quinate catalyzed by 3-dehydroquinate synthase. The mechanism of ring closure is complex, but involves an aldol condensation at C-2 and C-7.
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