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Query: EC:4.1.1.41 (propionyl-CoA carboxylase)
 344 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Methylmalonyl-CoA decarboxylase of Veillonella alcalescens catalyzed the isotopic exchange between methylmalonyl-CoA and [1-14C]propionyl-CoA or between malonyl-CoA and [1-14C]acetyl-CoA. The exchange was independent of sodium ions and was abolished by avidin. The enzyme also catalyzed the carboxyl transfer reaction from methylmalonyl-CoA to acetyl-CoA yielding propionyl-CoA and malonyl-CoA, and vice versa. The beta subunit was dissociated from methylmalonyl-CoA decarboxylase by prolonged washing of the enzyme while bound via its biotin prosthetic group to monomeric avidin-Sepharose. The beta-chain-depleted enzyme was inactive as a methylmalonyl-CoA decarboxylase but retained carboxyltransferase activity. The beta subunits were specifically protected by Na+ ions from tryptic hydrolysis. Based on these and other observations the following functions may be assigned to the different polypeptide chains of methylmalonyl-CoA decarboxylase: carboxyltransferase (alpha), carboxybiotin-carrier-protein decarboxylase (beta), biotin carrier protein (gamma). The function of the delta chain is unknown.
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PMID:The carboxyltransferase activity of the sodium-ion-translocating methylmalonyl-CoA decarboxylase of Veillonella alcalescens. 292 Jul 30

Mechanisms of growth inhibition by propionate on the growth of Rhodopseudomonas sphaeroides were studied. Partially purified pyruvate dehydrogenase complex (PDC) from R. sphaeroides was inhibited by propionyl-CoA, one of the metabolic intermediates of propionate, while propionate itself did not inhibit the enzyme. This suggests that the inhibitor of the growth in vivo is not propionate but propionyl-CoA. The inhibition by propionyl-CoA was competitive with respect to coenzyme A concentration. The K1 value for propionyl-CoA was 0.84 mM. Addition of NaHCO3, which restored the growth of this bacterium in the presence of propionate, increased the rate of propionate incorporation by 1.7-fold and decreased the intracellular level of propionyl-CoA by half. These findings suggest that HCO3-ion lowers the level of propionyl-CoA by accelerating its carboxylation reaction, which is catalyzed by propionyl-CoA carboxylase. Effects of NaHCO3 and acetate on the growth restoration were also studied by the use of propionyl-CoA carboxylase-deficient mutants. NaHCO3 did not restore the growth of the mutants, indicating an essential role of propionyl-CoA carboxylase on the restoration of growth by NaHCO3 as suggested above. Addition of acetate restores the growth of the mutants in the presence of propionate. Acetate probably restores the growth by supplying acetyl-CoA.
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PMID:Mechanisms of growth inhibition by propionate and restoration of the growth by sodium bicarbonate or acetate in Rhodopseudomonas sphaeroides S. 300 41

On the basis of enzyme activities detected in extracts of Selenomonas ruminantium HD4 grown in glucose-limited continuous culture, at a slow (0.11 h-1) and a fast (0.52 h-1) dilution rate, a pathway of glucose catabolism to lactate, acetate, succinate, and propionate was constructed. Glucose was catabolized to phosphoenol pyruvate (PEP) via the Emden-Meyerhoff-Parnas pathway. PEP was converted to either pyruvate (via pyruvate kinase) or oxalacetate (via PEP carboxykinase). Pyruvate was reduced to L-lactate via a NAD-dependent lactate dehydrogenase or oxidatively decarboxylated to acetyl coenzyme A (acetyl-CoA) and CO2 by pyruvate:ferredoxin oxidoreductase. Acetyl-CoA was apparently converted in a single enzymatic step to acetate and CoA, with concomitant formation of 1 molecule of ATP; since acetyl-phosphate was not an intermediate, the enzyme catalyzing this reaction was identified as acetate thiokinase. Oxalacetate was converted to succinate via the activities of malate dehydrogenase, fumarase and a membrane-bound fumarate reductase. Succinate was then excreted or decarboxylated to propionate via a membrane-bound methylmalonyl-CoA decarboxylase. Pyruvate kinase was inhibited by Pi and activated by fructose 1,6-bisphosphate. PEP carboxykinase activity was found to be 0.054 mumol min-1 mg of protein-1 at a dilution rate of 0.11 h-1 but could not be detected in extracts of cells grown at a dilution rate of 0.52 h-1. Several potential sites for energy conservation exist in S. ruminantium HD4, including pyruvate kinase, acetate thiokinase, PEP carboxykinase, fumarate reductase, and methylmalonyl-CoA decarboxylase. Possession of these five sites for energy conservation may explain the high yields reported here (56 to 78 mg of cells [dry weight] mol of glucose-1) for S. ruminantium HD4 grown in glucose-limited continuous culture.
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PMID:Pathway and sites for energy conservation in the metabolism of glucose by Selenomonas ruminantium. 314 85

Purified biotinidase (enriched 24,000-fold) from fresh human plasma exhibited reduced catalytic activity when incubated with heat-inactivated dialyzed plasma. The polypeptide fractions separated from the heat-inactivated dialyzed plasma using streptavidin-Sepharose resin showed the same effect on purified biotinidase. These inhibitory effects on biotinidase were partial (25-45%) rather than complete. The polypeptide fraction from streptavidin-Sepharose resin was analyzed by SDS-PAGE in the Laemmli system and by various types of HPLC. Analyses by ion-exchange and reversed-phase HPLC revealed the existence of three relatively small mol. wt polypeptides. Each of these peak fractions exhibited similar inhibitory effects on biotinidase activity. SDS-PAGE analysis indicated that the streptavidin affinity resin fraction was composed of four major polypeptides whose mol. wts were 120,000, 76,000, 53,000 and 27,000. The two bands of 120,000 and 76,000 corresponded to the mol. wts of the biotinyl subunit of pyruvate carboxylase, beta-methyl-crotonyl-CoA and/or propionyl-CoA carboxylase respectively. However, the polypeptides of mol. wts 53,000 and 27,000 were found to be two unique biotinyl-peptides present in human plasma. These bands on the gels were transblotted and exhibited a fluorescent activity after incubated with a FITC-avidin. These findings strongly suggest the existence of circulating plasma biotinyl-polypeptides as inhibitory factor(s) on human plasma biotinidase.
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PMID:Effect of plasma biotinyl-peptides on biotinidase activity. 325 55

The steric course of the decarboxylation of (S)-methylmalonyl-CoA to propionyl-CoA, catalyzed by the biotin-dependent sodium pump methylmalonyl-CoA decarboxylase of Veillonella alcalescens was determined. The decarboxylation of (S)-methylmalonyl-CoA in 3H2O yielded (R)-[2-3H]propionyl-CoA; and the decarboxylation of (S)-[2-3H]methylmalonyl-CoA in H2O produced (S)-[2-3H]propionyl-CoA. The results demonstrate retention of configuration during the decarboxylation reaction. The substrate stereochemistry of methylmalonyl-CoA decarboxylase is thus the same as that of all other biotin-containing enzymes investigated.
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PMID:Stereochemistry of the methylmalonyl-CoA decarboxylation reaction. 360 8

Affinity chromatography on avidin-Sepharose column was used to bind the biotin-containing carboxylases from rat liver. With a biotin gradient (0-0.3 mM), peaks of activity of pyruvate, propionly CoA and beta-methylcrotonyl CoA carboxylases co-eluted. Subsequent separation of the three carboxylases was attained using DEAE-Sepharose chromatography. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis showed each of the enzymes to be pure, with pyruvate carboxylase giving a single subunit band (Mr 130 000), propionyl-CoA carboxylase giving two bands (Mr 73 000 and 56 500) and beta-methylcrotonyl-CoA carboxylase giving two bands (Mr 75 000 and 60 000). The specific activity of propionyl-CoA carboxylase (15.8 munits/mg) and beta-methylcrotonyl-CoA carboxylase (24.2 munits/mg) were comparable with reported activities for these purified enzymes, while that of pyruvate carboxylase (1.25 munits/mg) was low. This is a suitable method for the simultaneous preparation of purified carboxylases for the specific purpose of raising antisera to these enzymes.
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PMID:Simultaneous preparation of the three biotin-containing mitochondrial carboxylases from rat liver. 399 77

[l-(14)C]Propionate administered intravenously was metabolized to methylmalonate, to 3-hydroxypropionate, and to methylcitrate in the urine of a patient with methylmalonic acidemia. L-[U-(14)C]Isoleucine and L-[U-(14)C]valine were also converted to urinary methylmalonate and to 3-hydroxypropionate in the patient. Two patients with propionic acidemia due to a defect in propionyl-CoA carboxylase metabolized [l-(14)C]propionate to uninary methylcitrate and 3-hydroxypropionate. The appearance of radioactive 3-hydroxypropionate in the urine after the administration of these compounds indicates that beta-oxidation of propionyl-CoA through acryloyl-CoA was functioning in these patients. The conversion of valine to 3-hydroxypropionate suggests that valine is oxidized by way of propionate and propionyl-CoA in man.
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PMID:3-hydroxypropionate: significance of -oxidation of propionate in patients with propionic acidemia and methylmalonic acidemia. 450 4

A heat-stable endogenous CO(2) acceptor has been found in extracts of Rhodospirillum rubrum grown photoheterotrophically on acetate. Evidence is presented which suggests that this factor is propionic acid. Thus, paper and gas chromatographic analyses have indicated that propionic acid is present in boiled extracts prepared from R. rubrum cells. The products of (14)CO(2) fixation obtained with either the boiled extract or propionic acid as the CO(2) acceptor were identical and were identified as methylmalonic acid and succinic acid by paper chromatography. The enzyme which catalyzes the carboxylation of propionyl-coenzyme A (propionyl-CoA carboxylase) was purified from R. rubrum cells grown on acetate and its properties were studied. The enzyme is similar to propionyl-CoA carboxylases isolated from mammalian sources.
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PMID:Identification of propionate as an endogenous CO2 acceptor in Rhodospirillum rubrum and properties of purified propionyl-coenzyme A carboxylase. 565 84

Malonyl-CoA decarboxylase from the uropygial gland of goose decarboxylated (R,S)-methylmalonyl-CoA at a slow rate and introduced 3H from [3H]2O into the resulting propionyl-CoA. Carboxylation of this labeled propionyl-CoA by propionyl-CoA carboxylase from pig heart and acetyl-CoA carboxylase from the uropygial gland completely removed 3H. Repeated treatment of (R,S)-[methyl-14C]methylmalonyl-CoA with the decarboxylase converted 50% of the substrate into propionyl-CoA, whereas (S)-methylmalonyl-CoA, generated by both carboxylases, was completely decarboxylated. Radioactive (R)- (S), and (R,S)-methylmalonyl-CoA were equally incorporated into fatty acids by fatty acid synthetase from the uropygial gland. The residual methylmalonyl-CoA remaining after fatty acid synthetase reaction on (R,S)-methylmalonyl-CoA was also racemic. These results show that: (a) the decarboxylase is stereospecific, (b) replacement of the carboxyl group by hydrogen occurs with retention of configuration, (c) acetyl-CoA carboxylase of the uropygial gland generates (S)-methylmalonyl-CoA from propionyl-CoA, and (d) fatty acid synthetase is not stereospecific for methylmalonyl-CoA.
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PMID:Stereospecificity of malonyl-CoA decarboxylase, acetyl-CoA carboxylase, and fatty acid synthetase from the uropygial gland of goose. 610 30

The trematode, Fasciola hepatica, and the cestode, Spirometra mansonoides have been shown to be similar to the nematode Ascaris lumbricoides in that all three decarboxylate succinate to propionate plus CO2. Associated with this decarboxylation is an incorporation of 32Pi into organic phosphate. Both the decarboxylation and phosphorylation are markedly stimulated by the addition of propionyl-CoA, are dependent on coenzyme B12 and are inhibited by avidin. The trematode and cestode exhibit propionyl-CoA carboxylase, methylmalonyl-CoA mutase and acyl-CoA transferase activities in sonicated mitochondrial preparations. Data are consistent with the occurrence of a mitochondrial substrate level site for ATP generation which is coupled with the decarboxylation of succinate. In Fasciola preparations, acetyl-CoA stimulates the decarboxylation and phosphorylation to a considerably larger extent than propionyl-CoA, indicating the possibility that acetyl-CoA may serve physiologically in these reactions by donating the CoA moiety to succinate.
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PMID:Succinate decarboxylation to propionate and the associated phosphorylation in Fasciola hepatica and Spirometra mansonoides. 611 29


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