Glucose Phosphate Isomerase Activity Research Articles

Melatonin induces resistance against Penicillium expansum in apple fruit through enhancing phenylpropanoid metabolism

Apple fruit is delicious fruit with great economic value. However, harvested apples are susceptible to the infection of Penicillium expansum, which results in quality degradation. ‘Golden Delicious’ apples were dipped with melatonin solution to investigate its influence on blue mold and the dynamic changes of the major metabolites contents and enzymes activities in phenylpropanoid metabolism. Melatonin markedly suppressed lesion development of P. expansum-inoculated apple fruit. Melatonin dipping also distinctly improved 4-coumarate coenzyme A ligase, cinnamic acid 4-hydroxylase, phenylalanine ammonia lyase, polyphenol oxidase, laccase, glucose-6-phosphate dehydrogenase, and glucose phosphate isomerase activities. Moreover, p-coumaric acid, total phenolic compounds, ferulic acid, flavonoids, erucic acid, caffeic acid, lignin, phenylalanine, tyrosine, and tryptophan contents were also enhanced by melatonin. All these findings indicate that melatonin treatment activates the key enzyme activity in phenylpropanoid metabolism to accelerate metabolites accumulation in apples, therefore inducing resistance to blue mold.

Trehalose maintains the quality of Malus domestica by mediating sucrose and respiratory metabolism

Quality breakdown and decay are the main factors that cause economic losses of fruit and vegetable during storage. Apple fruit (cv. Golden Delicious) were dipped in 1.5 g L−1 trehalose to investigate the changes of quality parameters, activity and gene expression of key enzyme in sucrose and respiratory metabolism. Results showed that trehalose treatment suppressed weight loss and respiratory rate, maintained soluble solid content and flesh firmness in apples. Moreover, trehalose suppressed neutral invertase (NI) and sucrose synthase cleavage (SS-c), cytochrome oxidase (CCO) and succinate dehydrogenase (SDH), glucose phosphate isomerase activities and MdNI, MdSS, MdSDH and MdCCO expressions in apple fruit. Meanwhile, trehalose increased the activities of sucrose phosphate synthase (SPS), sucrose synthase synthesis (SS-s) and glucose 6-phosphate dehydrogenase (G6PDH), and MdSPS, MdG6PDH and MdPFK expressions in apples. These results propose that trehalose treatment maintains storage quality of apples by regulating sucrose and respiratory metabolism during storage.

Expression and Knockdown Analysis of Glucose Phosphate Isomerase in Chicken Primordial Germ Cells1

Glucose is an important monosaccharide required to generate energy in all cells. After entry into cells, glucose is phosphorylated to glucose-6-phosphate and then transformed into glycogen or metabolized to produce energy. Glucose phosphate isomerase (GPI) catalyzes the reversible isomerization of glucose-6-phosphate and fructose-6-phosphate. Without GPI activity or fructose-6-phosphate, many steps of glucose metabolism would not occur. The requirement for GPI activity for normal functioning of primordial germ cells (PGCs) needs to be identified. In this study, we first examined the expression of chicken GPI during early embryonic development and germ cell development. GPI expression was strongly and ubiquitously detected in chicken early embryos and embryonic tissues at Embryonic Day 6.5 (E6.5). Continuous GPI expression was detected in PGCs and germ cells of both sexes during gonadal development. Specifically, GPI expression was stronger in male germ cells than in female germ cells during embryonic development and the majority of post-hatching development. Then, we used siRNA-1499 to knock down GPI expression in PGCs. siRNA-1499 caused an 85% knockdown in GPI, and PGC proliferation was also affected 48 h after transfection. We further examined the knockdown effects on 28 genes related to the glycolysis/gluconeogenesis pathway and the endogenous glucose level in chicken PGCs. Among genes related to glycolysis/gluconeogenesis, 20 genes showed approximately 3-fold lower expression, 4 showed approximately 10-fold lower, and 2 showed approximately 100-fold lower expression in knockdown PGCs. The endogenous glucose level was significantly reduced in knockdown PGCs. We conclude that the GPI gene is crucial for maintaining glycolysis and supplying energy to developing PGCs.

Hereditary non-spherocytic hemolytic anemia and severe glucose phosphate isomerase deficiency in an Indian patient homozygous for the L487F mutation in the human GPI gene

Homozygous glucose phosphate isomerase (GPI) deficiency is one of the most important erythroenzymopathies causing hereditary non-spherocytic hemolytic anemia (HNSHA). We report an Indian patient with HNSHA showing 85 % reduction in GPI activity resulting from a homozygous missense replacement g.1459C > T in exon 16, leading to a substitution of the protein residue L487F mutation. This mutation has been detected previously in a compound heterozygous state along with another mutation in a GPI deficient patient elsewhere. To our knowledge, this is the first report of HNSHA associated with GPI deficiency with the homozygous L487F mutation, as well as the first report from India of GPI deficiency. Molecular modeling using the human crystal structure of GPI as a model was performed to determine how this mutation could affect enzyme structure and function. The enzyme is present in a dimeric form necessary for normal activity; the L487F mutation causes a loss of the ability of GPI to dimerize, which decreases the thermostability of the enzyme and results in significant changes in erythrocyte metabolism.

Red cell glucose phosphate isomerase (GPI): a molecular study of three novel mutations associated with hereditary nonspherocytic hemolytic anemia

Molecular characteristics of red blood cell (RBC) glucose phosphate isomerase (GPI) deficiency are described in two Spanish patients with chronic nonspherocytic hemolytic anemia. One patient, with residual GPI activity in RBCs of around 7% (GPI-Catalonia), is homozygous for the missense mutation c.1648A>G (p.Lys550Glu) in exon 18. The other patient, with residual activity in RBCs of around 20% (GPI-Barcelona), was found to be a compound heterozygote for two different missense mutations: c.341A>T (p.Asp113Val) in exon 4 and c.663T>G (p.Asn220Lys) in exon 7. Molecular modeling using the human crystal structure of GPI as a model was performed to determine how these mutations could affect enzyme structure and function.

Effect of furfural on carbon metabolism key enzymes of lactose-assimilating yeasts

The metabolic response of lactose-assimilating yeasts to changes of cultivation conditions after addition of furfural into the medium was explored. Two yeast strains were studied— Candida blankii 35 with an oxidative metabolism, and C. pseudotropicalis 11 with a fermentative metabolism. Strains were cultivated in a chemostat under carbon limitation and dilution rates D = 0.1 and 0.25 h −1. During the transition period after a shock treatment with 0.04% furfural, changes of the following enzymes of the carbon metabolism were studied: hexokinase (HK), glucosephosphate isomerase (GPI) and glyceraldehyde-3P-dehydrogenase (GAPD) of the glycolysis, glucose-6P-dehydrogenase (GPD) from the pentosophosphate cycle, as well as β-galactosidase. Results show that during cultivation of C. pseudotropicalis 11 at D = 0.1 h −1, furfural concentration of 0.04% caused increase of the glycolytic enzyme activities, while the level of GPD activity remained rather constant. At the higher dilution rate D = 0.25 h −1 the effect of furfural brought to a significant decrease of all enzyme activities studied, except β-galactosidase, for which activity registered at both dilution rates was significantly higher. During cultivation of C. blankii 35 at D = 0.1 h −1, furfural brought to lower activities of GPI and GPD, while HK activity was not affected by the inhibitor, and that of GAPD increased. The furfural shock at D = 0.25 h −1 leads to increased activity of the three glycolytic enzymes, while that of GPD was 33.6% lower as compared to control. Addition of furfural into the cultivation medium of the oxidative strain caused decrease of β-galactosidase activity.

Glucose phosphate isomerase deficiency: enzymatic and familial characterization of Arg346His mutation

Homozygous glucose phosphate isomerase (GPI) deficiency is one of the most important genetic disorders responsible for chronic non-spherocytic hemolytic anemia (CNSHA), a red blood cell autosomal recessive genetic disorder which causes severe metabolic alterations. In this work, we studied a patient with CNSHA due to an 82% loss of GPI activity resulting from the homozygous missense replacement in cDNA position 1040G>A, which leads to substitution of the protein residue A346H mutation. The enzyme is present in a dimeric form necessary for normal activity; the A346H mutation causes a loss of GPI capability to dimerize, which renders the enzyme more susceptible to thermolability and produces significant changes in erythrocyte metabolism.

Combined glucose-6-phosphate dehydrogenase and glucosephosphate isomerase deficiency can alter clinical outcome

Glucosephosphate isomerase (GPI) deficiency in humans is an autosomal recessive disorder, which results in nonspherocytic hemolytic anemia of variable clinical expression. A 4-year-old female with severe congenital hemolytic anemia had low red cell GPI activity of 15.5 IU/g Hb (50% of normal mean) indicating GPI deficiency. Subsequent DNA sequence analysis revealed a novel homozygous 921C to G mutation in the GPI gene sequence, predicting a Phe307 to Leu replacement. Strikingly, the red cell GPI activity in this patient was higher than that found in a second patient expressing the same GPI variant, with a more severe clinical phenotype. We propose that the hemolysis in the first patient may be modified by an accompanying deficiency of glucose-6-phosphate dehydrogenase (G6PD). The proband’s red cell G6PD activity was reduced at 4.5 IU/g Hb (50% of normal mean) and molecular studies revealed heterozygosity for the G6PD Viangchan mutation and a skewed pattern of X-chromosome inactivation, producing almost exclusive expression of the mutated allele. The G6PD Viangchan variant is characterised by severe enzyme deficiency, but not chronic hemolysis. This study suggests that the metabolic consequences of a combined deficiency of GPI and G6PD might be responsible for a different clinical outcome than predicted for either defect in isolation.

Effect of Cholesterol-Enriched Diet on Liver and Heart Enzymes in Male Rabbits

White New Zealand male rabbits were fed a high-cholesterol (1%) diet for 7 weeks. The activity of alkaline phosphatase (AP), alanine (AlaAT), aspartate (AspAT) aminotransferases and level of glucose in the blood plasma of rabbits was determined and compared with those of a control group of animals. The cholesterol-enriched diet resulted in increases in plasma AlaAT and AP activity and a decrease in plasma glucose. In the liver, cholesterol treatment decreased the activity of AspAT, AlaAT, AP, phosphoglucomutase, phosphofructokinase, pyruvate kinase and lactate dehydrogenase. Activities of glucosephosphate isomerase, aldolase and the level of glycogen were not affected. No statistically significant changes in the activity of examined enzymes in heart of rabbits fed with cholesterol-enriched diet were observed. Chronic intake of cholesterol in the diet had a negative effect on liver metabolism but not on heart metabolism in rabbits.

Isoenzymes of Eimeria from the domestic fowl: electrophoretic variants among species, strains and clones.

Electrophoretic variation of enzymes in five Eimeria spp. of the domestic fowl, including nine strains, ten single-sporocyst clones and two single-sporozoite clones of E. acervulina, three strains each of E. maxima and E. tenella, two strains of E. praecox and one strain of E. necatrix, were assayed using cellulose acetate electrophoresis. Ten enzymes [aldehyde oxidase (AO), alkaline phosphatase (ALP), amylase (AMY), fumarate hydratase (FUM), glucose-6-phosphate dehydrogenase (G6PDH), glucose phosphate isomerase (GPI), glutamate-oxaloacetate transferase (GOT), isocitrate dehydrogenase (IDH), malate dehydrogenase (MDH) and phosphoglucomutase (PGM)] were analyzed for their ability to distinguish between these species and strains. Enzymatic activity of G6PDH, GPI, IDH, MDH and PGM was detected in all the Eimeria spp. examined. Strains within each species were characterized by the same electrophoretic variant of G6PDH. Electrophoretic variants of GPI and PGM were the most valuable in the identification of inter- and intra-specific variation, particularly in the field strains of E. acervulina and E. tenella. These two enzymes were used to examine single-sporocyst and single-sporozoite clones derived from two strains of E. acervulina. The enzymes in E. maxima appeared to be conserved, showing no variation among strains with the five enzymes detected. Relative mobilities, calculated as described in this paper, were found to be consistent between different electrophoresis runs and may serve as a reference when this medium is used.

Molecular Analysis of Glucose Phosphate Isomerase Deficiency Associated With Hereditary Hemolytic Anemia

We report here two new cases of glucose phosphate isomerase (GPI) deficiency associated with hemolytic anemia and present the results of molecular analysis of the five Japanese GPI variants. A Japanese girl (GPI Fukuoka) had an episode of prolonged neonatal jaundice and at 3 years of age was admitted due to acute hemolytic crisis occurring with upper respiratory tract infection. Red blood cell (RBC) GPI activity was decreased to 11.8% of normal and the reduced glutathione (GSH) level of RBCs was slightly decreased. A 54-year-old Japanese man (GPI Iwate) was hospitalized due to chronic active hepatitis, and compensated hemolysis was noted. RBC GPI activity of the proband was decreased to 18.8%, and the GSH content was about half of the normal mean value. Sequencing of the reticulocyte GPIcDNA showed homozygous missense mutations 1028CAG-->CGG (343Gln-->Arg), 14ACC-->A7C (5Thr-->lle), 671ACG-->A7G (224Thr-->Met), and 1615GAC-->AAC (539Asp-->Asn) in GPI Narita, GPI Matsumoto, GPI Iwate, and GPI Fukuoka, respectively. We also identified GPI Kinki as a compound heterozygote of 1124ACA-->AGA(375Thr-->Arg)/ 1615GAC-->AAC(539Asp-->Asn). Our findings, together with the previous results of other investigators, showed that the GPI gene mutations so far identified were heterogeneous, although most GPI variants had common biochemical characteristics such as heat instability and normal kinetics. Several amino acid substitutions were identified in the proximity of the catalytically important amino acid residues such as Ser/Asp 159/160, Asp341, and Lys518, which have been identified in the structural analysis of the pig GPI. The molecular characterization of human GPI variants, therefore, may provide new insights into the genotype-phenotype correlation of GPI deficiency as well as the structure-function relationship of this enzyme.

Comparative erythrocyte metabolism in marsupials and monotremes

Concentrations of ATP and DPG, activities of 10 enzymes and the glycolytic rates were measured in the erythrocytes of 11 species of marsupials and two species of monotremes. Mean DPG concentrations were greater in the erythrocytes of marsupials than those of eutherian mammals. The opposite is true of ATP. Significant findings from the results of enzyme activities were: high activity of hexokinase (7.39 ± 0.82 EU/g Hb) in the short-beaked echidna, pyruvate kinase (37.49 ± 1.0 EU/g) Hb in bridled nailtail wallaby and glucose-6-phosphate dehydrogenase (G6PD; 41.66 ± 1.24 EU/g Hb) in black-striped wallaby. About 6- to 7-fold difference in the activity of G6PD levels between the two species of wombats was confirmed. Glucose phosphate isomerase activity was also shown to be twice as high in the red cells of the common wombat compared with those of the southern hairy nosed wombat. There were wide variations in the glycolytic rate among the species examined.

Isoenzyme variation within the genus Cryptosporidium.

Soluble extracts of the oocysts of Cryptosporidium parvum had demonstrable, but low, activities of malate dehydrogenase (MDH, EC. 1.1.1.37), carboxylesterase (ES, EC 3.1.1.1) and lactate dehydrogenase (LDH, EC. 1.1.1.27) following thin-layer starch-gel electrophoresis. Much higher activities of glucose phosphate isomerase (GPI, EC. 5.3.1.9) and phosphoglucomutase (PGM, EC. 2.7.5.1) were found, and zymograms of these two enzymes were used to characterise isolates of C. parvum from human, bovine, ovine and cervine sources, C. muris from the brown rat and C. baileyi from young turkeys. PGM and GPI zymograms clearly distinguished between C. parvum, C. muris and C. baileyi. The five isolates of C. parvum showed the same electrophoretic mobility for GPI, whereas the PGM mobility of the single human isolate of C. parvum examined was clearly different from that of the other isolates. This is the first report of the use of isoenzymes to distinguish between species and isolates of Cryptosporidium.

Fusion of Sunflower Protoplasts: Isoenzyme Analysis and Regeneration Capacity

Hypocotyl protoplasts isolated from two sunflower cultivars were electrically fused and subsequently cultivated. After about six weeks of culture, crude extracts of the generated calli were analyzed by starchgel electrophoresis. The gels were stained for the isoenzyme activities of glucosephosphate isomerase and malate dehydrogenase, which allow discrimination between the cultivars used for the fusion experiment. About 26% of the calli generated from pulsed protoplasts showed isoenzyme patterns of putative binary heterokaryocytes. The isoenzyme pattern of the nonfused control revealed less than 5% of possible chimeric colonies. Additionally, in a similar type of experiment, different culture regimes of the protoplasts were investigated. Calli treated with relatively high auxin concentrations generated somatic embryos, however, mostly those originating from electrostimulated protoplasts.

Studies on the blood of fallow deer (Dama dama) and red deer (Cervus elaphus): haematology, red cell enzymes, metabolic intermediates and glycolytic rates.

1. Blood samples were obtained from fallow deer (Dama dama) and red deer (Cervus elaphus). Basic haematology, red cell enzymes, and metabolic intermediates and the glycolytic rate of the red cells incubated with different substrates were measured. 2. The major findings were (i) the activity of glucose phosphate isomerase was notably high in the red blood cells of the red deer; (ii) red deer cells also utilized adenosine more efficiently than those of fallow deer and (iii) red cells of both species utilized galactose more efficiently than other species of ruminants.

Identification and purification of glucose phosphate isomerase of Plasmodium falciparum

The multiplication of malaria parasites within red blood cells is energy dependent. Since these parasites lack a functional tricarboxylic acid cycle, the energy needs of the parasite are met by anaerobic glycolysis of exogenous glucose. High levels of glycolytic enzymes such as fructose-1,6-diphosphate aldolase, phosphoglycerate kinase and pyruvate kinase have been detected in infected erythrocytes. Here we report a 4–9 times increase in glucose phosphate isomerase (GPI) activity of infected erythrocytes over that of normal erythrocytes. This increase is of parasitic origin, as additional enzyme bands were observed in lysates of infected erythrocytes. The expression of GPI parallels parasite maturation and reaches a maximum at the trophozoite/schizont stage. Two distinct but closely related activity patterns consisting of 3–4 GPI isoenzymes (not shown in normal erythrocytes) with neutral to weakly acidic isoelectric points were observed in 6 P. falciparum isolates tested by isoelectric focusing. The purified P. falciparum GPI has an apparent size of 66 kDa. No size variation was observed in the 6 P. falciparum isolates studied. Furthermore, antiserum raised against this protein in BALB/c mice specifically inhibits parasite encoded GPI activity while no effect was observed on host enzyme activity.

Genetic differences in glucose phosphate isomerase activity among mouse embryos.

We have compared mouse embryos of three heterozygous, congenic genotypes (with high, medium and low levels of oocyte-coded glucose phosphate isomerase (GPI-1) activity respectively) to test whether 1) the survival time of oocyte-coded GPI-1 activity in the early embryo is affected by its activity level in the oocyte and 2) whether embryo-coded GPI-1 is detected earlier in embryos that inherit low levels of oocyte-coded GPI-1. The oocyte-coded GPI-1 was entirely GPI-1A allozyme in the high and medium groups but was the less stable GPI-1C allozyme in the low group. We determined total GPI-1 activity and the ratio of different GPI-1 allozymes in early embryos and calculated the activity of oocyte-coded and embryo-coded GPI-1. In all three groups, the oocyte-coded enzyme activity remained at a more or less constant level for the first 21 1/2 days. Some oocyte-coded GPI-1 remained in 4 1/2 day embryos from the high and medium groups but was gone by 5 1/2 days. Very little remained in 4 1/2 day embryos that inherited low levels of a less stable form of the enzyme (GPI-1C allozyme). Despite a 4- to 5-fold difference in initial oocyte-coded GPI-1 activity, no differences were seen among the three genotypically distinct groups of embryos in the time of activation of the embryonic Gpi-1s genes. The embryo-coded GPI-1 was first detectable in 3 1/2 day compacted morulae in all three groups. The level of oocyte-coded GPI-1, in the high group, when embryo-coded GPI-1 was first detected was higher than the level in the low group at any stage prior to detection of embryo-coded GPI-1.(ABSTRACT TRUNCATED AT 250 WORDS)

Dry weight accumulation and starch‐synthesis enzymes in grain of cultured ears of three winter wheat varieties

Detached ears of three winter wheat (Triticum aestivum L.) varieties were cultured in solution for 12 days with sucrose levels varying from 36.5 to 292 mM. The dry weight and starch content of grains increased asymptotically with the sucrose level in the solution. At 4 days of culture, glucose phosphate isomerase (EC 5.3.1.9) activity grain−1 was lower with 36.5 mM than with higher sucrose levels in the medium; at 8 days, adenosinc diphosphoglucose pyrophosphorylase (EC 2.7.7.27) and (soluble plus bound) starch synthase (EC 2.4.1.21) activities grain−1 were higher with 146 and 292 mM sucrose than with 36.5 and 73 mM sucrose. The multiple regression of starch content over these enzyme activities showed that starch synthase was relatively more important as an independent variable. The dry weight and starch content of grains were higher in the variety Maris Huntsman than in Splendeur and Hobbit. The water content of grains was lower in Splendeur than in the other two varieties. At 4 days the glucose phosphate isomerase, adenosine diphosphoglucose pyrophosphorylase and starch synthase activities grain−1 were smaller in Splendeur than in Hobbit and Maris Huntsman and al 8 days they were higher in Maris Huntsman than in Hobbit and Splendeur. The varietal differences in starch content of grains were related to the activities of glucose phosphate isomerase and especially of starch synthase.

Electrophoretic variants of enzymes in isolates of Plasmodium falciparum, P. malariae and P. vivax from Thailand

A new electrophoretic variant of glucose phosphate isomerase (GPI), which we now denote GPI-3, has been found in isolates of Plasmodium falciparum from 6 patients, all of whom acquired the infection in the same region (in or near Prachinburi province) of Thailand. In other regions, from which 453 isolates have been tested, only GPI-1 and/or GPI-2 have been found. Two isolates of P. malariae from patients at Kanchanaburi showed a band of GPI activity on cellulose acetate gels at a cathodal position quite distinct from that of any previously known GPI variants in other human malaria parasites. Thirtynine isolates of P. vivax from 3 regions of Thailand have been examined for variants of GPI and lactate dehydrogenase (LDH). Three forms of GPI were found, corresponding approximately in band positions to GPI-1, 2 and 3 of P. falciparum. The position of the band of LDH activity in P. vivax was the same in all the isolates examined, and different from that of LDH-1 in P. falciparum.

Non-additive inheritance of glucose phosphate isomerase activity in mice heterozygous at theGpi-1sstructural locus

The activity of blood glucose phosphate isomerase (GPI-1) in mice heterozygous for various alleles at the Gpi-1s structural locus (heterozygotes a/b, a/c and b/c) was significantly higher than expected, on the basis of additive inheritance, from the levels in parental homozygotes. Moreover, the GPI-1 activity was higher in a/b heterozygotes than in either parent (heterosis). Studies of heat stability with kidney homogenates revealed that the relative stabilities of GPI-1 dimers was AA greater than AB greater than BB greater than AC greater than or equal to BC greater than CC. Differences in dimer stabilities in vivo would affect the total GPI-1 levels in heterozygotes and could account for non-additive inheritance but would be insufficient to explain heterosis for GPI-1 activity. Other possible contributing factors include unequal production or stability of monomers, or higher catalytic activity of heterodimers. Monomers could also associate non-randomly but this would not be sufficient to explain heterosis. It is clear that non-additive inheritance patterns may be produced by variants of either structural or regulatory genes.