SEARCH · PubMed Health

Results for “Pyruvate Decarboxylase”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 397 records · Page 22Linked to original sources

PubMed1976

Pyrithiamine-induced thiamine deficiency: effects on rat myelination.

Pyrithiamine was administered to newborn rats throughout the vulnerable period for myelinogenesis. A major metabolic defect was produced in the cerebral activities of the thiamine-dependent enzymes, transketolase and pyruvate decarboxylase. In spite of a defect in carbohydrate metabolism which is lethal in adult rats, overall development, and myelination as indicated by biochemical and morphological criteria, proceeded at an essentially normal rate. These findings indicate alternative metabolic pathways may be operational in newborn rat brain enabling it to circumvent major blockage in thiamine-dependent reactions.

Animals↗

PubMed1998

Thiamin-dependent enzymes as catalysts in chemoenzymatic syntheses.

Enzymes are increasingly being used to perform regio- and enantioselective reactions in chemoenzymatic syntheses. To utilize enzymes for unphysiological reactions and to yield novel products, a broad substrate spectrum is desirable. Thiamin diphosphate (ThDP)-dependent enzymes vary in their substrate tolerance from rather strict substrate specificity (phosphoketolases, glyoxylate carboligase) to more permissive enzymes (transketolase, dihydroxyacetone synthase, pyruvate decarboxylase) and therefore differ in their potential to be used as biocatalysts. We give an overview of the known substrate spectra of ThDP-dependent enzymes and present examples of multi-enzyme or chemoenzymatic approaches which involve ThDP-dependent enzymes as biocatalysts to obtain pharmaceutical compounds as ephedrine and glycosidase inhibitors, sex pheromones as exo-brevicomin, 13C-labeled metabolites, and other intermediates as 1-deoxyxylulose 5-phosphate, a precursor of vitamins and isoprenoids.

Aldehyde-Ketone Transferases↗

PubMed2001

Enzymes of the Entner-Doudoroff and pyruvate decarboxylation pathways in Zymomonas mobilis wild-type CP4 and mutant strains grown in continuous culture.

The osmotolerant Zymomonas mobilis strain suc40, (containing plasmid pDS3154-inaZ), which is capable of producing simultaneously ethanol and ice nuclei protein, was cultivated in a chemically defined complete sucrose medium, as well as in a sugar beet molasses medium in continuous culture. The strain exhibited the normal Monod's relationship between biomass and dilution rate, and between growth substrate concentration and dilution rate. Specific activities of a number of enzymes that appear to control important steps in the metabolic flux of the Entner-Doudoroff and pyruvate decarboxylation pathways were investigated over a range of growth rates in steady state cultures. With the exception of glucose-6-phosphate dehydrogenase and gluconate kinase, all of the enzymes exhibited a very similar pattern for the wild type Z. mobilis CP4 and for the osmotolerant mutants, independent of the media used; the enzyme patterns remained relatively constant over the studied growth range. The specific activity of glucose-6-phosphate dehydrogenase was increased 2-fold by decreasing dilution rate in sugar beet molasses. The specific activity of gluconate kinase was 2-fold lower at medium growth rates compared with that at either low or high growth rates. Pyruvate kinase, pyruvate decarboxylase and alcohol dehydrogenase activities were significantly higher compared with those of the enzymes governing the early steps of the Entner-Doudoroff pathway. The present study, which was designed to determine the behaviour of important enzymes in sucrose metabolism of Z. mobilis suc40/pDS3154-inaZ grown in continuous culture showed that the microorganism required regulation of specific enzyme activities at the transcriptional level when sugar beet molasses were used as the growth medium.

Alcohol Dehydrogenase↗

PubMed1992

Biosynthesis and characterization of 3-hydroxyalkan-2-ones and 2,3-alkanediols: potential products of aldehyde metabolism.

A mass spectrometric study of an enzymatic synthesis of 3-hydroxyalkan-2-ones (acyloins) is presented. Incubation of pyruvate or (13C3)pyruvate and various alkanals in the presence of pig heart pyruvate dehydrogenase or yeast pyruvate decarboxylase resulted in the formation of acyloins with chains two carbons longer than the alkanals. Product formation was rapid for all saturated aldehydes with chain lengths from 2 to 12 carbons. Incubation with 2,3-unsaturated aldehydes did not produce condensation products. Reduction of acyloins with sodium borohydride produced the corresponding 2,3-alkanediols. Analysis by gas chromatography/mass spectrometry was used to characterize the 3-hydroxyalkan-2-ones as the oxime-trimethylsilyl derivatives and the 2,3-alkanediols as the bistrimethylsilyl derivatives.

Aldehydes↗

PubMed2000

Theoretical indicators of enzyme reaction specificity from conserved information in amino acid sidechains.

Amino acid sequences for 11 acetohydroxy acid synthase (EC 4.1.3.18; AHS) polypeptides with experimentally established activity were chosen for computational comparisons to detect conserved local information associated with reaction specificity for each sequence. Windowed analysis by Pearson product moment cross-correlation of six amino acid sidechain properties revealed locally conserved segments common to all proteins with AHS activity. Seven information segments were detected in the same arrangement in sequences for the large subunit polypeptides of prokaryotes, and in the sequences for single polypeptides of eukaryotic AHS. The information segments were numbered 1-7 according to sequential position, and sequence features such as cofactor binding sites were defined for specific segments. Extension of the information segment analysis to seven other proteins of the pyruvate decarboxylase superfamily permitted use of the content and organization of information segments to recognize four classes of enzyme reaction specificity. Estimates of information entropy, based upon a state space defined by reaction specificity, directly reflected the known reaction complexity for all but one enzyme examined. Our data suggest that development of information-segment models for enzyme superfamilies may improve the accuracy of inferring protein activity from sequence.

Acetolactate Synthase↗

PubMed2001

Conversion of xylose to ethanol by recombinant Saccharomyces cerevisiae: importance of xylulokinase (XKS1) and oxygen availability.

The yeast Saccharomyces cerevisiae efficiently ferments hexose sugars to ethanol, but it is unable to utilize xylose, a pentose sugar abundant in lignocellulosic materials. Recombinant strains containing genes coding for xylose reductase (XR) and xylitol dehydrogenase (XDH) from the xylose-utilizing yeast Pichia stipitis have been reported; however, such strains ferment xylose to ethanol poorly. One reason for this may be the low capacity of xylulokinase, the third enzyme in the xylose pathway. To investigate the potential limitation of the xylulokinase step, we have overexpressed the endogenous gene for this enzyme (XKS1) in S. cerevisiae that also expresses the P. stipitis genes for XR and XDH. The metabolism of this recombinant yeast was further investigated in pure xylose bioreactor cultivation at various oxygen levels. The results clearly indicated that overexpression of XKS1 significantly enhances the specific rate of xylose utilization. In addition, the XK-overexpressing strain can more efficiently convert xylose to ethanol under all aeration conditions studied. One of the important illustrations is the significant anaerobic and aerobic xylose conversion to ethanol by the recombinant Saccharomyces; moreover, this was achieved on pure xylose as a carbon. Under microaerobic conditions, 5.4 g L(-1) ethanol was produced from 47 g L(-1) xylose during 100 h. In fed-batch cultivations using a mixture of xylose and glucose as carbon sources, the specific ethanol production rate was highest at the highest aeration rate tested and declined by almost one order of magnitude at lower aeration levels. Intracellular metabolite analyses and in vitro enzyme activities suggest the following: the control of flux in a strain that overexpresses XKS1 has shifted to the nonoxidative steps of the pentose phosphate pathway (i.e., downstream of xylose 5-phosphate), and enzymatic steps in the lower part of glycolysis and ethanol formation pathways (pyruvate kinase, pyruvate decarboxylase, and alcohol dehydrogenase) do not have a high flux control in this recombinant strain. Furthermore, the intracellular ATP levels were found to be significantly lower for the XK strain compared with either the control strain under similar conditions or glucose-grown Saccharomyces. The ATP : ADP ratios were also lower for the XK strain, especially under microaerobic conditions (0.9 vs 6.4).

Aerobiosis↗

PubMed1993

Disruption of the Kluyveromyces lactis GGS1 gene causes inability to grow on glucose and fructose and is suppressed by mutations that reduce sugar uptake.

In the yeast Saccharomyces cerevisiae the GGS1 gene is essential for growth on glucose or other readily fermentable sugars. GGS1 is the same gene as TPS1 which was identified as encoding a subunit of the trehalose-6-phosphate synthase/phosphatase complex and it is allelic to the fdp1, byp1, glc6 and cif1 mutations. Its precise function in the regulation of sugar catabolism is unknown. We have cloned the GGS1 homologue from the distantly related yeast Kluyveromyces lactis. The KlGGS1 gene is 74% and 79% identical at the nucleotide and amino acid sequence level, respectively, to the S. cerevisiae counterpart. We also compared the sequence with the partly homologous products of the S. cerevisiae genes TPS2 and TSL1 which code for the larger subunits of the trehalose synthase complex and with a TSL1 homologue, TPS3, of unknown function. Multiple alignment of these sequences revealed several particularly well conserved elements. Disruption of GGS1 in K. lactis caused the same pleiotropic phenotype as in S. cerevisiae, i.e. inability to grow on glucose or fructose and strongly reduced trehalose content. We have also studied short-term glucose-induced regulatory effects related to cAMP and cAMP-dependent protein kinase, i.e. the cAMP signal, trehalase activation, trehalose mobilization and inactivation of fructose-1,6-bisphosphatase. These effects occur very rapidly in S. cerevisiae and are absent in the Scggs1 mutant. In K. lactis all these effects were much slower and largely unaffected by the Klggs1 mutation. On the other hand, glucose strongly induced pyruvate decarboxylase and activated the potassium transport system in K. lactis and both effects were absent in the Klggs1 mutant. Addition of glucose to galactose-grown cells of the Klggs1 mutant caused, as in S. cerevisiae, intracellular accumulation of free glucose and of sugar phosphates and a rapid drop of the ATP and inorganic phosphate levels. Glucose transport kinetics were the same for the wild type and the Klggs1 mutant in both derepressed cells and in cells incubated with glucose. We have isolated phenotypic revertants of the Klggs1 mutant for growth on fructose. The suppressors that we characterized had, to different extents, diminished glucose uptake in derepressed cells but cells incubated in glucose showed very different characteristics. The suppressor mutations prevented deregulation of glycolysis in the Klggs1 mutant but not the accumulation of free glucose. The mutants with higher residual uptake activity showed partially restored induction of pyruvate decarboxylase and activation of potassium transport.(ABSTRACT TRUNCATED AT 400 WORDS)

Amino Acid Sequence↗

PubMed1985

Biochemical study in 28 children with lactic acidosis, in relation to Leigh's encephalomyelopathy.

An enzymatic study of cultured skin fibroblasts was made in 28 patients with lactic acidosis. In three of these patients a diagnosis of Leigh's encephalomyelopathy was established from autopsy findings. Pyruvate decarboxylase (PDC) deficiency was found in four patients. In two of them, in whom Leigh's encephalomyelopathy was proved by autopsy, PDC activity was lower than 10% of the normal. The other two living patients, who showed 22%-25% of the normal activity, had clinical symptoms and courses different from Leigh's disease. These findings suggest that the patients with severe PDC deficiency develop Leigh's disease but those with mild deficiency may not. A deficiency of cytochrome c oxidase was found in two siblings. One of them, who was diagnosed as having Leigh's encephalomyelopathy by postmortem examination, showed a reduction of cytochrome c oxidase in the liver and brain. In the other sibling, who is living, the reduction of cytochrome c oxidase was demonstrated in the cultured skin fibroblasts and biopsied muscle. In an electron-microscopic study of biopsied muscle, two patients with mitochondrial myopathy were found. Their fundamental enzymatic defects were unclear. In two patients, in whom Leigh's disease was suspected following a brain CT, the production of 14CO2 from [3-14C] pyruvate was found to be low; suggesting a reduced activity of the TCA cycle. In another 18 patients, the fundamental defect was not clear.

Acidosis↗

PubMed1997

How thiamine diphosphate is activated in enzymes.

The controversial question of how thiamine diphosphate, the biologically active form of vitamin B1, is activated in different enzymes has been addressed. Activation of the coenzyme was studied by measuring thermodynamics and kinetics of deprotonation at the carbon in the 2-position (C2) of thiamine diphosphate in the enzymes pyruvate decarboxylase and transketolase by use of nuclear magnetic resonance spectroscopy, proton/deuterium exchange, coenzyme analogs, and site-specific mutant enzymes. Interaction of a glutamate with the nitrogen in the 1'-position in the pyrimidine ring activated the 4'-amino group to act as an efficient proton acceptor for the C2 proton. The protein component accelerated the deprotonation of the C2 atom by several orders of magnitude, beyond the rate of the overall enzyme reaction. Therefore, the earlier proposed concerted mechanism or stabilization of a C2 carbanion can be excluded.

Allosteric Regulation↗

PubMed2003

Enhanced low oxygen survival in Arabidopsis through increased metabolic flux in the fermentative pathway.

We manipulated the enzyme activity levels of the alcohol fermentation pathway, pyruvate decarboxylase (PDC), and alcohol dehydrogenase (ADH) in Arabidopsis using sense and antisense overexpression of the corresponding genes (PDC1, PDC2, and ADH1). Transgenic plants were analyzed for levels of fermentation and evaluated for changes in hypoxic survival. Overexpression of either Arabidopsis PDC1 or PDC2 resulted in improved plant survival. In contrast, overexpression of Arabidopsis ADH1 had no effect on flooding survival. These results support the role of PDC as the control step in ethanol fermentation. Although ADH1 null mutants had decreased hypoxic survival, attempts to reduce the level of PDC activity enough to see an effect on plant survival met with limited success. The combination of flooding survival data and metabolite analysis allows identification of critical metabolic flux points. This information can be used to design transgenic strategies to improve hypoxic tolerance in plants.

Alcohol Dehydrogenase↗

PubMed1984

Regulation of enzymes and isoenzymes of carbohydrate metabolism in the yeast Saccharomyces cerevisiae.

An electrophoretic method has been devised to investigate the changes in the enzymes and isoenzymes of carbohydrate metabolism, upon adding glucose to derepressed yeast cells. (i) Of the glycolytic enzymes tested, enolase II, pyruvate kinase and pyruvate decarboxylase were markedly increased. This increase was accompanied by an overall increase in glycolytic activity and was prevented by cycloheximide, an inhibitor of protein synthesis. (ii) In contrast, respiratory activity decreased after adding glucose. This decrease was clearly shown to be the result of repression of respiratory enzymes. A rapid decrease within a few minutes of adding glucose, by analogy with the so-called ' Crabtree effect', was not observed in yeast. (iii) The gluconeogenic enzymes, fructose-1,6-bisphosphatase and malate dehydrogenase, which are inactivated after adding glucose, showed no significant changes in electrophoretic mobilities. Hence, there was no evidence of enzyme modifications, which were postulated as initiating degradation. However, it was possible to investigate cytoplasmic and mitochondrial malate dehydrogenase isoenzymes separately. Synthesis of the mitochondrial isoenzyme was repressed, whereas only cytoplasmic malate dehydrogenase was subject to glucose inactivation.

Fructose-Bisphosphatase↗

PubMed1980

Glycolytic enzymes and intermediates in carbon catabolite repression mutants of Saccharomyces cerevisiae.

Glycolytic parameters were determined in recessive yeast mutants with partial defects in carbon catabolite repression. Specific activities of pyruvate kinase and pyruvate decarboxylase in glucose grown cells of all mutant and wild type strains were 4--5 times higher than in ethanol grown cells. Mutants of gene HEX1 had a reduced hexose phosphorylating activity on all media whereas those of gene HEX2 had elevated levels but only in glucose grown cells. Mutants of gene CAT80 were normal in this respect. All other glycolytic enzymes were normal in all mutants. This was also true for glycolytic intermediates. Only hex1-mutants showed a reduced fermentation of repressing sugars. The three genes appear to be involved in catabolite repression of several but not of all repressible enzymes. Even though all three types of mutants show a limited overlap in their effects on certain enzymes, they still are distinctly different in their action spectra. Carbon catabolite repression apparently does not depend on the sole accumulation of glycolytic intermediates. The activity of the products of the three genes HEX1, HEX2 and CAT80 are required directly or indirectly for triggering carbon catabolite repression. Even a small segment of carbon catabolite repression is controlled by several genes with regulatory functions indicating that the entire regulatory circuit is highly complex.

Carbon↗

PubMed2004

Biochemical and molecular characterization of alpha-ketoisovalerate decarboxylase, an enzyme involved in the formation of aldehydes from amino acids by Lactococcus lactis.

In this paper, we report for the first time on the identification, purification, and characterization of the alpha-ketoisovalerate decarboxylase from Lactococcus lactis, a novel enzyme responsible for the decarboxylation into aldehydes of alpha-keto acids derived from amino acid transamination. The kivd gene consisted of a 1647 bp open reading frame encoding a putative peptide of 61 kDa. Analysis of the deduced amino acid sequence indicated that the enzyme is a non-oxidative thiamin diphosphate (ThDP)-dependent alpha-keto acid decarboxylase included in the pyruvate decarboxylase group of enzymes. The active enzyme is a homo-tetramer that showed optimum activity at 45 degrees C and at pH 6.5 and exhibited an inhibition pattern typical for metal-dependant enzymes. In addition to Mg(2+), activity was observed in presence of other divalent cations such as Ca(2+), Co(2+) and Mn(2+). The enzyme showed the highest specific activity (80.7 Umg(-1)) for alpha-ketoisovalerate, an intermediate metabolite in valine and leucine biosynthesis. On the other side, decarboxylation of indole-3-pyruvate and pyruvate only could be detected by a 100-fold increase in the enzyme concentration present in the reaction.

Aldehydes↗

PubMed2000

Engineering of the pyruvate dehydrogenase bypass in Saccharomyces cerevisiae: role of the cytosolic Mg(2+) and mitochondrial K(+) acetaldehyde dehydrogenases Ald6p and Ald4p in acetate formation during alcoholic fermentation.

Acetic acid plays a crucial role in the organoleptic balance of many fermented products. We have investigated the factors controlling the production of acetate by Saccharomyces cerevisiae during alcoholic fermentation by metabolic engineering of the enzymatic steps involved in its formation and its utilization. The impact of reduced pyruvate decarboxylase (PDC), limited acetaldehyde dehydrogenase (ACDH), or increased acetoacetyl coenzyme A synthetase (ACS) levels in a strain derived from a wine yeast strain was studied during alcoholic fermentation. In the strain with the PDC1 gene deleted exhibiting 25% of the PDC activity of the wild type, no significant differences were observed in the acetate yield or in the amounts of secondary metabolites formed. A strain overexpressing ACS2 and displaying a four- to sevenfold increase in ACS activity did not produce reduced acetate levels. In contrast, strains with one or two disrupted copies of ALD6, encoding the cytosolic Mg(2+)-activated NADP-dependent ACDH and exhibiting 60 and 30% of wild-type ACDH activity, showed a substantial decrease in acetate yield (the acetate production was 75 and 40% of wild-type production, respectively). This decrease was associated with a rerouting of carbon flux towards the formation of glycerol, succinate, and butanediol. The deletion of ALD4, encoding the mitochondrial K(+)-activated NAD(P)-linked ACDH, had no effect on the amount of acetate formed. In contrast, a strain lacking both Ald6p and Ald4p exhibited a long delay in growth and acetate production, suggesting that Ald4p can partially replace the Ald6p isoform. Moreover, the ald6 ald4 double mutant was still able to ferment large amounts of sugar and to produce acetate, suggesting the contribution of another member(s) of the ALD family.

Acetates↗

PubMed1979

Amino acid changes in thiamine-deficient encephalopathy: some implications for the pathogenesis of Friedreich's ataxia.

Thiamine-deficient encephalopathy in the rat is characterized by ataxic gait, loss of righting reflex and curvature of the spine. Neurochemical changes include a diminished activity of cerebral pyruvate decarboxylase leading to abnormal pyruvate oxidation. The present study shows that this defective pyruvate oxidation produces a significant depletion of three important amino acid neurotransmitters, namely gamma aminobutyric acid (GABA), glutamic acid, and aspartic acid. Such changes could lead to severe neuronal dysfunction and the observed neurological symptoms of thiamine deficiency. Some implications for the pathogenesis of Friedreich's ataxia are discussed.

Amino Acids↗

PubMedDate not supplied

Metabolic flux variation of Saccharomyces cerevisiae cultivated in a multistage continuous stirred tank reactor fermentation environment.

The technique of metabolic flux analysis was implemented to elucidate the flux balancing of Saccharomyces cerevisiae cultivated in a multistage continuous stirred tank reactor fermentation environment. The results showed that the majority of the substrate (97.70 +/- 0.49%) was funneled into the glycolytic pathway, while the remainder was subdivided between the pentose phosphate pathway and pathways for polysaccharide synthesis. At the pyruvate node, 87.30 +/- 1.38% of the flux was channeled through the reaction governed by pyruvate decarboxylase. Fluxes through the pyruvate dehydrogenase bypass were maintained at a constant level (82.65 +/- 1.47%) irrespective of the configuration of the fermentation setup. Activity through the TCA "cycle" was replenished by the reaction catalyzed by pyruvate carboxylase and by the transport of cytosolic oxaloacetate across the mitochondrial membrane. The CO(2) evolution rate varied as fermentation progressed; however, the yield coefficient of CO(2) remained at a constant value. Although a constant yield of ethanol (0.42 g of ethanol/g of glucose) was obtained, operations of the TCA cycle were gradually switched from partially reductive to partially oxidative pathways from the first fermenter to the fourth fermenter.

Alcoholic Beverages↗

PubMed1983

Wild-type and mutant forms of the pyruvate dehydrogenase multienzyme complex from Bacillus subtilis.

A simple procedure is described for the purification of the pyruvate dehydrogenase complex and dihydrolipoamide dehydrogenase from Bacillus subtilis. The method is rapid and applicable to small quantities of bacterial cells. The purified pyruvate dehydrogenase complex (s0(20),w = 73S) comprises multiple copies of four different types of polypeptide chain, with apparent Mr values of 59 500, 55 000, 42 500 and 36 000: these were identified as the polypeptide chains of the lipoate acetyltransferase (E2), dihydrolipoamide dehydrogenase (E3) and the two types of subunit of the pyruvate decarboxylase (E1) components respectively. Pyruvate dehydrogenase complexes were also purified from two ace (acetate-requiring) mutants of B. subtilis. That from mutant 61142 was found to be inactive, owing to an inactive E1 component, which was bound less tightly than wild-type E1 and was gradually lost from the E2E3 subcomplex during purification. Subunit-exchange experiments demonstrated that the E2E3 subcomplex retained full enzymic activity, suggesting that the lesion was limited to the E1 component. Mutant 61141R elaborated a functional pyruvate dehydrogenase complex, but this also contained a defective E1 component, the Km for pyruvate being raised from 0.4 mM to 4.3 mM. The E1 component rapidly dissociated from the E2E3 subcomplex at low temperature (0-4 degrees C), leaving an E2E3 subcomplex which by subunit-exchange experiments was judged to retain full enzymic activity. These ace mutants provide interesting opportunities to analyse defects in the self-assembly and catalytic activity of the pyruvate dehydrogenase complex.

Bacillus subtilis↗

PubMed2000

Inactivation of the stress- and starvation-inducible gls24 operon has a pleiotrophic effect on cell morphology, stress sensitivity, and gene expression in Enterococcus faecalis.

Enterococcus faecalis induces the synthesis of at least 42 proteins during 24 h of glucose starvation. Because of its induction during carbohydrate and complete starvation (incubation in tap water) and CdCl(2) and bile salts stresses, one of these proteins (Gls24) was qualified as a "general stress protein" and was analyzed at the molecular level. Its corresponding gene, gls24, seems to be the penultimate gene of an operon composed, altogether, of six open reading frames (ORFs). The ORF preceding gls24 (orf4) showed very strong identity with gls24. The deduced polypeptides of these two genes showed similarity with a 20-kDa hypothetical protein from Lactococcus lactis and an alkaline stress protein from Staphylococcus aureus with no previously known biological significance. Data from the operon sequence and Northern analysis led to the conclusions that (i) gls24 possesses its own promoter which is especially induced at the onset of starvation and (ii) the operon promoter is stress inducible in exponential-phase cells. A mutation in the gls24 gene led to a severe reduction of growth rate and reduction of survival against 0.3% bile salts in the 24-h-starved cells compared to the wild-type strain. Moreover, the chain length of the mutant is significantly reduced during growth. These results argue strongly for a role of the protein Gls24 and/or GlsB in morphological changes and in stress tolerance in E. faecalis. Comparison of two-dimensional protein gels from wild-type cells with those from gls24 mutant cells revealed a pleiotropic effect of the mutation on gene expression. At least nine proteins were present in larger amounts in the mutant. For six of them, the corresponding N-terminal microsequence has been obtained. Three of these sequences map in genes coding for L-lactate dehydrogenase, lipoamide dehydrogenase, and pyruvate decarboxylase, all involved in pyruvate metabolism.

Amino Acid Sequence↗