Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
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The PGI1 gene of Saccharomyces cerevisiae coding for the glycolytic enzyme phosphoglucose isomerase has been cloned by complementation of a mutant strain (pgi1) with a strongly reduced phosphoglucose isomerase activity. A genomic library constructed in the yeast multicopy vector YEp13 (Nasmyth and Tatchell 1980) was used. Four plasmids containing an overlapping region of 4.1 kb were isolated and characterized by restriction endonuclease mapping. Southern analysis of genomic digests prepared with different restriction enzymes confirmed the same pattern for the chromosomal sequences. Transformants with the isolated plasmids had a phosphoglucose isomerase activity increased by a factor of 7. The cloned sequence hybridized to a constitutively synthesized 2.2 kb RNA in Northern analysis. The coding region includes a 2.05 kb EcoRI fragment common to all four inserts. A fragment including part of the PGI1 region was subcloned into vector YRp7 and used to induce integration at the PGI1 locus. Genetical and Southern analysis of stable transformants showed that single as well as tandem integration took place at this locus. This showed that the PGI1 gene had been isolated. Finally, and in contrast to the results of Kempe et al. (1974a, b) who reported three isoenzymes in yeasts, only one copy of the PGI1 gene per genome was found in several laboratory strains tested by Southern analysis.
Mol Gen Genet 1986 Jan
PMID:Isolation and molecular analysis of the phosphoglucose isomerase structural gene of Saccharomyces cerevisiae. 300 40

Glycolytic enzymes in the purified glycosomes of Trypanosoma brucei brucei bloodstream forms were crosslinked to form a large protein complex by the bifunctional reagent dimethyl suberimidate [Aman, R.A., Kenyon, G.L. and Wang, C.C. (1985) J. Biol. Chem. 260, 6966-6973]. The crosslinked enzyme complex was found capable of catalyzing the chain reactions leading from glucose to the formation of alpha-glycerophosphate in the presence of ATP and NADH. To determine whether the crosslinked enzyme complex exhibits multiple substrate channelings, these chain reactions were investigated in the crosslinked complex as well as in a preparation of solubilized native glycosomes. When glucose was present at a relatively high concentration (20 mM), production of alpha-glycerophosphate by the crosslinked complex had no apparent lag phase whereas the free enzyme mixture did. However, when the glucose level was lower (0.5-5.0 mM) the difference between the two enzyme preparations disappeared, a lag phase was found in both cases. Formation of sugar phosphates from radiolabeled glucose, followed by high performance liquid chromatographic analysis, showed no significant difference in the diluting powers of exogenous, unlabeled sugar phosphates added to the crosslinked complex or free enzymes. Exogenous fructose 1,6-diphosphatase demonstrated the same effectiveness in disrupting the chain reactions catalyzed by the crosslinked complex and the free enzyme mixture. In situ generation of 2-deoxyglucose-6-phosphate from 2-deoxyglucose and ATP was observed in the crosslinked complex, but the product had no amplified inhibitory effect on the phosphoglucose isomerase activity in the complex. All results suggest an absence of substrate channelings among the glycolytic enzymes in the glycosome of T. b. brucei bloodstream form.
Mol Biochem Parasitol 1986 Apr
PMID:Absence of substrate channeling in the glycosome of Trypanosoma brucei. 301 32

The structural gene PGI1 coding for phosphoglucose isomerase was replaced by the LEU2 gene in the genome of Saccharomyces cerevisiae. Plasmids carrying the LEU2 gene between genomic regions flanking the PGI1 gene were constructed and used to transform a PGI1/pgi1 diploid strain. Stable transformants lacking the PGI1 allele were isolated. Southern analysis of their meiotic products showed that haploid strains with a deletion of 1.6 kb within the 2.2 kb PGI1 coding region were viable. Thus, the PGI1 gene is not essential in yeasts. However, unlike pgi1 mutants with residual phosphoglucose isomerase activity, no growth was detected in the pgi1 delta haploid strains when fructose was supplied as sole carbon source. The wild-type growth rate could be restored by adding 0.1% glucose to the medium. Furthermore, pgi1 mutants with residual enzymatic activity grew very slowly on fructose-supplemented media containing up to 2% glucose. Strains carrying the deletion allele, however, failed to grow at glucose concentrations higher than 0.5%. Also the pgi1 delta strains did not grow in glucose as sole carbon source. On the other hand pgi1 delta/pgi1 delta diploid strains did not sporulate on the usual acetate medium. This defect could be alleviated by the addition of 0.05% glucose to the sporulation medium. Under these conditions the pgi1 delta mutants sporulated with an efficiency of 25% compared with the wild type. These results suggest that the phosphoglucose isomerase reaction is the only step catalysing the interconversion of glucose-6-P and fructose-6-P, glucose-6-P is essential in yeasts, and the oxidation of glucose-6-P through the glucose-6-P dehydrogenase reaction is not sufficient to support growth in yeasts.
Mol Gen Genet 1986 Aug
PMID:Deletion of the phosphoglucose isomerase structural gene makes growth and sporulation glucose dependent in Saccharomyces cerevisiae. 302 Mar 69

We have cloned and sequenced the PGI1 gene, encoding phosphoglucose isomerase (E.C.5.3.1.9), from Saccharomyces cerevisiae. The nucleotide sequence predicts subunits of 554 amino acids with a molecular weight of 61,230. Both the size and amino acid composition correlate well with measurements from purified protein. We have compared the PGI1 protein with the predicted sequence for pig muscle PGI. In spite of some evolutionary divergence the proteins are very similar and there are some highly conserved regions, two of which have been implicated in the active site. It has been suggested that PGI exists in two or more isozyme forms in S. cerevisiae and analogy with ADR2/ADC1 suggests that such PGI isozymes might also be differentially regulated during glycolytic/gluconeogenic growth. We have used accurate quantitation of PGI1 mRNA and gene fusions of PGI1 to the lacZ gene of Escherichia coli to show that PGI1 transcription is regulated neither between glycolytic and gluconeogenic growth nor between exponential and stationary phase. The complete lack of PGI activity in PGI1 deletion mutants and of differential regulation suggests that the isozymes of PGI might result merely from processing of the PGI1 gene product.
Mol Gen Genet 1988 Dec
PMID:The structure and regulation of phosphoglucose isomerase in Saccharomyces cerevisiae. 307 35

The activities of the key enzymes of ribulose monophosphate cycle for formaldehyde oxidation and assimilation were tested in crude extracts from temperature sensitive mutants of obligatemethylotroph M. flagellatum KT. Two mutants deficient in phosphoglucoisomerase activity were identified during this screening. Phosphoglucoisomerase of T525 pgi-1 mutant was active both at permissive (30 degrees C) and nonpermissive (42 degrees C) temperatures. Complete inactivation of the enzyme at 42 degrees C occurred in 2 h in vitro, while in vivo incubation at nonpermissive temperature for more than 10 h was required for the enzyme inactivation. Phosphoglucoisomerase activity of T566 pgi-2 was 5-fold lower as compared with the one from the parent strain incubated at 30 degrees C. The enzyme was inactivated in 2 min. in crude extract at nonpermissive temperature.
Mol Gen Mikrobiol Virusol 1987 Aug
PMID:[Characteristics of Methylobacillus flagellatum KT mutants, deficient for phosphoglucoisomerase, an enzyme of the ribulose monophosphate cycle of obligate methylotrophic bacteria]. 311 97

Proteins in malaria parasites (Plasmodium falciparum) isolated from a patient in Thailand before treatment, and after recrudescence of infection subsequent to mefloquine treatment, were compared by two dimensional polyacrylamide gel electrophoresis (2D-PAGE) analysis. Nine 'pre-treatment' and six 'recrudescent' clones were studied. Variants of the enzyme glucose phosphate isomerase were also noted and mefloquine susceptibility of each clone was measured by in vitro tests. The 'pre-treatment' isolate was found to contain at least four genetically distinct clones, all sensitive to mefloquine, while the 'recrudescent' isolate contained at least two other types of clone, both showing increased tolerance to mefloquine. These two more tolerant types of clone differed from all the sensitive ones studied in regard to several different protein variants as shown by 2D-PAGE analysis. It is concluded that at least two (and probably more) genetically distinct clones of parasites with increased tolerance to mefloquine were present in the parasite population before mefloquine treatment was given, and were selected under mefloquine pressure.
Mol Biochem Parasitol 1987 Mar
PMID:Polymorphism of proteins in malaria parasites following mefloquine treatment. 355 40

The glycosomes of in vitro grown procyclic trypomastigote forms of Trypanosoma brucei were purified by three different procedures and the results compared by electron microscopy, enzyme assays and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Centrifugation on a self-forming Percoll gradient followed by a sucrose gradient centrifugation resulted in the least enriched glycosomal preparation. Centrifugation on a pre-formed Nycodenz gradient gave an improved preparation but the most homogeneous preparation of intact glycosomes was obtained after centrifugation on two successive sucrose gradients. Glycosomes purified by both the Nycodenz and double sucrose gradient procedures appeared larger than in situ glycosomes presumably due to an osmotic effect resulting from disruption of the granular matrix of the organelles. Nevertheless, there appears to be no loss of cisternal contents due to the swelling of the organelles. The glycosomes of the bloodstream form trypomastigotes purified by the same procedures show, however, no sign of swelling. A comparison of glycosomes purified from procyclic trypomastigotes and bloodstream form trypomastigotes prepared by the same double sucrose procedure demonstrated that in the glycosome of procyclic trypomastigotes: activities of hexokinase, phosphoglucose isomerase, phosphofructose kinase, aldolase and phosphoglycerate kinase and diminished by 80-100%; activities of glyceraldehyde-3-phosphate dehydrogenase, triose phosphate isomerase and glycerol-3-phosphate dehydrogenase remain unchanged or are only slightly reduced; there is an appearance of four major new proteins, among which could be phosphoenol pyruvate carboxykinase and malate dehydrogenase. These observations are in basic agreement with those by Hart et al. (Mol. Biochem. Parasitol. 12, 25-35, 1984).
Mol Biochem Parasitol 1986 Dec
PMID:An improved purification of glycosomes from the procyclic trypomastigotes of Trypanosoma brucei. 380 43

Homologues of glucosephosphate isomerase (GPI, EC 5.3.1.9) were purified to homogeneity and kinetically characterized from Mytilus edulis and Isognomon alatus, two bivalve molluscs experiencing contrasting thermal environments. The enzyme isolated from I. alatus functions at warmer temperatures (25-35 C) than GPI from M. edulis, a species that inhabits colder marine littoral habitats (5-20 C). The former exhibits apparent first-order (with respect to substrate) catalytic rate constants (Vmax/KM) in vitro that become progressively greater than the mussel enzyme as the assay temperature is raised. Apparent zero-order catalytic rate constants (Vmax) are relatively less differentiated. Catalytic efficiency, defined as the rate at which a catalytic event occurs in either reaction direction for reference standard states (substrate concentrations), is greater for the enzyme from the tropical species (I. alatus) at all realistic combinations of temperature and substrate concentration except for the lowest temperatures and highest substrate concentrations, where the GPI from the boreal/temperate M. edulis is more efficient. This pattern of catalytic divergence appears to be due primarily to differentiation in Vmax/KM. These results and other published data are reviewed and shown to be inconsistent with claims that adaptation of enzymes to higher cell temperatures requires a loss in catalytic efficiency.
Mol Biol Evol 1985 May
PMID:The adaptation of enzymes to temperature: catalytic characterization of glucosephosphate isomerase homologues isolated from Mytilus edulis and Isognomon alatus, bivalve molluscs inhabiting different thermal environments. 387 Aug 60

1H spin echo NMR spectra of intact hepatocytes, isolated from rat liver, showed resonances for glucose, mobile fatty acids, and +N(CH3)3 groups including choline headgroups of phosphoglycerides. Spectra from extracts of the same cells contained many more well resolved resonances due to low Mr metabolites. These included signals for free amino acids, ketone bodies, glucose, lactate, and acetate. 1H NMR spectra from suspensions of intact hepatocytes incubated with acetaminophen showed no resonances for drug metabolites, although changes in sugar resonances were observed. However, spectra of extracts from acetaminophen-treated hepatocytes contained resonances for both acetaminophen itself and its major metabolites, the glucuronide and sulfate conjugates. Results on the extent of acetaminophen metabolism as measured by 1H NMR compared well with previously reported chromatographic studies. The rate of metabolism of acetaminophen by hepatocytes was much slower in 2H2O buffer compared to H2O buffer and selective deuteration of several metabolites including the ketone bodies, glucose, and acetaminophen glucuronide was observed. The deuteration of glucose C2H appeared to be due to futile cycling of the glycolytic pathway to at least fructose 6-phosphate, and incorporation of deuterium by the enzyme phosphoglucoisomerase. This work demonstrates that 1H NMR studies of intact hepatocytes and cell extracts together can provide considerable insight into the metabolism of acetaminophen in vitro. Little pretreatment of samples is required, results can be obtained rapidly, and both normal and drug metabolites can be observed simultaneously. Similar studies should be applicable to a wide range of other drugs.
Mol Pharmacol 1985 Jun
PMID:A high resolution proton nuclear magnetic resonance approach to the study of hepatocyte and drug metabolism. Application to acetaminophen. 400 Jan 8

Several restriction fragment length variants have been detected among inbred strains using a mouse serum amyloid A cDNA clone. Five variants were shown to segregate as a single genetic unit and were mapped to Chromosome 7 between the glucose phosphate isomerase locus (Gpi-1) and the pink eye dilution locus (p) using recombinant inbred and congenic strains. The finding that no major MspI or BclI restriction fragments were shared between digests of DNAs from a Chromosome 7 congenic strain and its inbred partner, indicate that most, and probably all, sequences detected with the probe are clustered on Chromosome 7. Aneuploid mapping was used to show that the serum amyloid A gene complex (Saa) is proximal to the Chromosome 7 breakpoint in T(7;X)1Ct, a translocation in which the middle third of Chromosome 7 is inserted into the X-chromosome. A survey of inbred strains revealed a single common Saa haplotype and eight rare haplotypes. The complex distribution of 14 different variants suggests that recombination may have played a role in haplotype evolution.
Mol Gen Genet 1984
PMID:Genes for serum amyloid A proteins map to Chromosome 7 in the mouse. 608 46


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