Decarboxylase

Pyruvate decarboxylase (EC 4.1.1.1) was isolated and purified from the yeast Kluyveromyces lactis. The properties of this enzyme relating to the native oligomeric state, the subunit size, the nucleotide sequence of the coding gene(s), the catalytic activity, and protein fluorescence as well as circular dichroism are very similar to those of the well characterized pyruvate decarboxylase species from yeast.

8p system191 01-06-2013 43 3   Download

Mikrobiologisches Institut der Eidgeno¨ssischen Technischen Hochschule, ETH-Zentrum, Zu¨rich, Switzerland The membrane-bound b subunit of the oxaloacetate decarboxylase Na+ pump of Klebsiella pneumoniae catalyzes the decarboxylation of enzyme-bound biotin. This event is coupled to the transport of 2 Na+ ions into the periplasm and consumes a periplasmically derived proton. The connecting fragment IIIa and transmembrane helices IV and VIII of the b subunit are highly conserved, harboring residues D203, Y229, N373, G377, S382, and R389 that play a profound role in catalysis. ...

8p system191 01-06-2013 33 4   Download

Antizyme is a polyamine-induced cellular protein that binds to ornithine decarboxylase (ODC), and targets it to rapid ubiquitin-independent degradation by the 26S proteasome. However, the metabolic fate of antizyme is not clear. We have tested the stability of antizyme in mammalian cells. In contrast with previous studies demonstrating stability in vitro in a reticulocyte lysate-based degradation system, in cells antizyme is rapidly degraded and this degradation is inhibited by specific proteasome inhibitors. ...

7p research12 01-06-2013 43 3   Download

Glutamate decarboxylase is a pyridoxal 5¢-phosphate-dependent enzyme responsible for the irreversiblea-decar-boxylation of glutamate to yield 4-aminobutyrate. In Escherichia coli, as well as in other pathogenic and non-pathogenic enteric bacteria, this enzyme is a structural component of the glutamate-based acid resistance system responsible for cell survival in extremely acidic conditions (pH

8p tumor12 22-04-2013 32 3   Download

Mature, active mammalian histidine decarboxylase is a di-meric enzyme of carboxy-truncatedmonomers (
53 kDa). By using a biocomputational approach, we have generateda three-dimensional model of a recombinant 1/512 fragment of the rat enzyme, which shows kinetic constants similar to those of the mature enzyme purified from rodent tissues. This model, together with previous spectroscopic data, al-lowed us to postulate that the occupation of the catalytic center by the natural substrate, or by substrate-analogs, would induce remarkable changes in the conformation of the intact holoenzyme....

12p tumor12 20-04-2013 37 2   Download

Limitedproteolysis of the pyruvate decarboxylase (E1,a2b2 ) component of the pyruvate dehydrogenase (PDH) multi-enzyme complexofBacillus stearothermophilushas indicated the importance for catalysis of a site (Tyr281-Arg282) in the E1asubunit (Chauhan, H.J., Domingo, G.J., Jung, H.-I. & Perham, R.N. (2000)Eur. J. Biochem.267, 7158–7169). This site appears to be conserved in the a-subunit of hetero-tetrameric E1s and multiple sequence alignments suggest that there are additional conserved amino-acid residues in this region, part of a common pattern with the consensus sequence -YR-H-D-YR-DE-.

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Enterobacter cloacae, isolated from the rhizosphere of cucumbers, produces large amounts of indole-3-acetic acid. Indolepyruvate decarboxylase, the key enzyme in the biosynthetic pathway of indole-3-acetic acid, catalyses the formation of indole-3-acetaldehyde and carbon dioxide from indole-3-pyruvic acid. The enzyme requires the cofac-tors thiamine diphosphate andmagnesium ions for catalytic activity. Recombinant indolepyruvate decarboxylase was purified from the host Escherichia coli strain JM109....

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The thiamindiphosphate-dependent enzyme indolepyruvate decarboxylase catalyses the formationof indoleacetaldehyde from indolepyruvate, one step in the indolepyruvate path-way of biosynthesis of the plant hormone indole-3-acetic acid. The crystal structure of this enzyme fromEnterobacter cloacaehasbeendeterminedat 2.65 A˚ resolutionandrefined to a crystallographic R-factor of 20.5% (Rfree 23.6%). The subunit of indolepyruvate decarboxylase contains three domains of opena/btopology, whichare similar in structure to that of pyruvate decarboxylase. ...

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The enzymes pyruvate decarboxylase (E1) and dihydro-lipoyl dehydrogenase (E3) bind tightly but in a mutually exclusive manner to the peripheral subunit-binding domain (PSBD) of dihydrolipoyl acetyltransferase in the pyruvate dehydrogenase multienzyme complex of Bacillus stearo-thermophilus.

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Transketolase from baker’s yeast is a thiamin diphosphate-dependent enzyme in sugar metabolism that reconstitutes with various analogues of the coenzyme. The methylated analogues (4¢-methylamino-thiamin diphos-phate and N1¢-methylated thiamin diphosphate) of the native cofactor were used to investigate the function of the aminopyrimidine moiety of the coen-zyme in transketolase catalysis.

17p awards 06-04-2013 38 4   Download

The oxaloacetate decarboxylase Na + pumps OAD-1 and OAD-2 ofVibrio choleraeare composed of a peripherala-subunit associated with two integ-ral membrane-bound subunits (bandc). The a-subunit contains the carb-oxyltransferase domain in its N-terminal portion and the biotin-binding domain in its C-terminal portion. Thec-subunit plays a profound role in the assembly of the complex.

10p awards 05-04-2013 34 4   Download

Malonyl-CoA, a potent inhibitor of carnitine pamitoyl transferase-I (CPT-I), plays a pivotal role in fuel selection in cardiac muscle. Malonyl-CoA decarboxylase (MCD) cata-lyzes the degradation of malonyl-CoA, removes a potent allosteric inhibition on CPT-I and thereby increases fatty acid oxidation in the heart. Although MCDhas several Ser/ Thr phosphorylation sites, whether it is regulated by AMP-activated protein kinase (AMPK) has been controversial. We therefore overexpressed MCD(Ad.MCD) and consti-tutively active AMPK (Ad.

10p dell39 03-04-2013 37 3   Download

p-Hydroxyphenylacetate decarboxylase from Clostridium difficilecatalyses the decarboxylation ofp-hydroxyphenyl-acetate to yield the cytotoxic compoundp-cresol. The three genes encoding two subunits of the glycyl-radical enzyme and the activating enzyme have been cloned and expressed in Escherichia coli. The recombinant enzymes were used to reconstitute a catalytically functional system in vitro.In contrast with the decarboxylase purified fromC.

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We have previously demonstrated that wild-typeTrypanosoma cruziepi-mastigotes lack arginine decarboxylase (ADC) enzymatic activity as well as its encoding gene. A foreign ADC has recently been expressed in T. cruzi after transformation with a recombinant plasmid containing the complete coding region of the oatADCgene.

10p dell39 27-03-2013 33 2   Download

The crystal structure of pyruvate decarboxylase fromKluyveromyces lactis has been determined to 2.26 A˚ resolution. Like other yeast enzymes, Kluyveromyces lactispyruvate decarboxylase is subject to allosteric sub-strate activation. Binding of substrate at a regulatory site induces catalytic activity.

11p inspiron33 25-03-2013 41 4   Download

Streptomyces coelicolorandStreptomyces pilosusproduce desferrioxamine siderophores which are encoded by thedesABCDgene cluster.S. pilosusis used for the production of desferrioxamine B which is utilized in human medicine. We report the deletion of thedesA gene encoding a lysine decarboxylase in Streptomyces coelicolorA3(2).

13p galaxyss3 21-03-2013 50 3   Download

2-Amino 3-carboxymuconate 6-semialdehyde decarboxylase (ACMSD, EC 4.1.1.45) plays a key role in tryptophan catabolism. By diverting 2-amino 3-carboxymuconate semialdehyde from quinolinate production, the enzyme regulates NAD biosynthesis from the amino acid, directly affecting quinoli-nate and picolinate formation.

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Phenylpyruvate decarboxylase (PPDC) ofAzospirillum brasilense, involved in the biosynthesis of the plant hormone indole-3-acetic acid and the anti-microbial compound phenylacetic acid, is a thiamine diphosphate-depend-ent enzyme that catalyses the nonoxidative decarboxylation of indole- and phenylpyruvate.

13p galaxyss3 19-03-2013 40 3   Download

The majority of phosphatidylethanolamine, an essential component of yeast mitochondria, is synthesized by phosphatidylserine decarboxylase 1 (Psd1p), a component of the inner mitochondrial membrane. Here, we report that deletion of OXA1encoding an inner mitochondrial membrane protein translocase markedly affects the mitochondrial phosphatidyletha-nolamine level.

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Thiamin diphosphate-dependent decarboxylases form addition intermedi-ates between thiamin diphosphate (ThDP) and 2-ketoacids. Although it appears that the intermediate should react without the intervention of cata-lysts, evidence has clearly shown that Brønsted acid catalysis occurs through a pre-associated system.

12p vinaphone15 28-02-2013 30 2   Download