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At least 19 recordsLinked to original sources
PubMed1978

Biochemical genetics of a new glucosephosphate isomerase allele (Gpi-1c) from wild mice.

We have found a new allele at the structural locus for glucosephosphate isomerase (called Gpi-1c) in a population of wild mice. The Gpi-1c allele codes for an enzyme of greater cathodal electrophoretic mobility than either the Gpi-1a or Gpi-1b alleles found in the wild and in the SM/J and C57BL/6J inbred strains. Mice homozygous for Gpi-1c have erythrocyte enzyme activity reduced to 33% of normal levels, altered pH profile, lowered heat stability, and normal Km's when compared with SM/J and C57BL/6J mice. The activity of the enzyme in brain, liver, and kidney is not so markedly lowered, although the electrophoretic mobility, pH profile, and heat stability are altered in these tissues. Deficiencies of erythrocyte glucosephosphate isomerase in man, to this level, can cause severe hemolytic anemia. Homozygotes for Gpi-1c show only mild hematological symptoms. The frequency of Gpi-1c in wild populations of mice is discussed and the occurrence of a further rare allele Gpi-1d is reported.

Alleles↗
PubMed1978

A new mutant erythrocyte glucosephosphate isomerase (GPI) associated with GSH abnormality.

A case of congenital nonspherocytic haemolytic anaemia associated with a new abnormal glucosephosphate isomerase (GPI), GSH (reduced glutathione) deficiency, and instability and altered carbohydrate membrane composition is reported. The only functional abnormality of the mutant enzyme seems to be a marked instability to heat, urea, and guanidine-HCl. Family studies suggest that the propositus is doubly heterozygous for a maternal gene producing an inactive enzyme and a paternal gene responsible for a structural alteration causing marked lability of the coded enzyme. Experiments of incubation of normal GPI and the propositus's GPI with oxidizing and reducing agents seem to indicate that the abnormality resides in the SH groups of the mutant GPI.

Adolescent↗
PubMed1977

Glucosephosphate isomerase deficiency, a new variant in a Dutch family. Case report.

The clinical course and the biochemical findings are reported from a patient suffering from glucosephosphate isomerase (G.P.I EC 5.3.1.9) deficiency type Nijmegen. This disorder decleares itself as a non-spherocytic hemolytic anemia, presenting in the neonatal period. In the patient hemolysis was of the same degree during the years. However, trivial infections could often trigger an increase in hemolysis requiring treatment by blood transfusions. Enzyme studies revealed that the GPI deficiency in this patient was caused by a double heterozygous state for two different GPI deficient alleles. The presence of one of these deficient alleles in the proband's parents and grandparents, was not accompanied by any sign of hemolysis, as for instance a shortened red-cell survival.

Alleles↗
PubMed1978

Species identification in protozoa: glucosephosphate isomerase variation in the Paramecium aurelia group.

Results are presented for intra- and interspecies variation in electrophoretic mobility of the enzyme glucosephosphate isomerase in the Paramecium aurelia species complex. Three new observations have been made: (1) the hitherto indistinguishable species 1 and 5 can be distinguished on the basis of GPI electrophoretic mobility, (2) the degree of intraspecies variation is much higher for GPI than for the previously studied mitochondrial dehydrogenases and esterases, and (3) several of the enzymatic variants observed in one species are apparently indistinguishable from some found in other species. The intraspecies variants found have been shown to be allelic, and, on the basis of the enzyme patterns of the heterozygotes, it is proposed that GPI is a dimeric enzyme determined by two loci. In view of the use of enzyme variation as a means of species identification in protozoa, these results suggest that the use of such methods can lead to underestimating the number of species and possibly to misclassification. The implications of these findings together with the results obtained with Tetrahymena are discussed.

Animals↗
PubMed1978

A technique for detection and relative quantitative analysis of glucosephosphate isomerase isozymes from nanogram tissue samples.

An improved method for detecting and measuring the enzyme glucosephosphate isomerase after starch gel electrophoresis is described. Nitrocellulose filters are used in a gel overlay procedure which increases the sensitivity of the staining reaction and provides a simple means for accurate quantitation of the isozyme pattern. This staining technique may have wider application with other gel media and also with other enzymes.

Alleles↗
PubMed1976

Synchronous allelic expression at the glucosephosphate isomerase A and B loci in interspecific sunfish hybrids.

Allelic isozymes of glucosephosphate isomerase at the Gpi-A and -B loci were separated by starch gel electrophoresis in the warmouth (Lepomis gulosus) and green sunfish (L. cyanellus). The specific tissue distributions and developmental expressions of the GPI-A2, -AB, and -B2 isozymes were not different between these two species. The synchrony of allelic expression in normal intraspecific sunfish crosses was demonstrated by means of an electrophoretic variant at the Gpi-B locus. In embryos formed from warmouth x green sunfish hybrid crosses, the paternal GPI-A2 isozymes were first expressed at the same time in both reciprocal hybrids, at 21-25 hr after fertilization. The maternal and paternal GPI-B subunits were synchronously expressed in reciprocal hybrids just for prior to hatching. The parental allelic isozymes at both loci shoed codominant expression in all tissues of the mature F1 hybrids. These results are consistent with the absence of allelic asynchrony and inhibition in interspecific hybrids formed from more evolutionarily related species.

Age Factors↗
PubMed1979

Evidence for a triplicate set of glucosephosphate isomerase structural genes in hexaploid wheat.

The glucosephosphate isomerase (GPI)zymogram phenotypes of 46 aneuploid derivatives of the cultivar Chinese Spring of hexaploid wheat were determined. Variation was observed among the strains in the relative level of expression of three GPI isozymes. The relationships observed between chromosomal constitution and zymogram phenotype support the hypothesis that the three GPI isozymes are dimers composed of protomers encoded by a minimum of three homoeologous structural genes located one each in the short arms of chromosomes 1A, 1B, and 1D. The relative levels of expression per dose of chromosome arm of the products of the three arms differ in a manner consistent with the presence of a two-fold greater quantity of the product of 1BS than of the product of 1AS and of 1DS, indicating that 1BS may contain duplicate GPI structural genes.

Chromosome Mapping↗
PubMed1977

Congenital nonspherocytic hemolytic anemia associated with glucosephosphate isomerase deficiency: variant Paderborn.

The deficient red cell enzyme glucosephosphate isomerase (GPI) was characterized in a patient of German origin who had already been described, with congenital nonspherocytic hemolytic anemia, and in his heterozygous parents. The variant enzyme differs from the known GPI variant enzyme differs from the known GPI variants by the electrophoretic mobility, the thermal stability, and the leukocyte activity. No differences are found between normal GPI and the variant regarding the affinity to fructose-6-phosphate, the pH optimum and the thermal optimum. Since the electrophoretic pattern and the properties of the parenteral GPI are identical the propositus seems to be homozygous for an abnormal allele and not double-heterozygous as some other cases with GPI deficiency are. Recently, immunological studies have shown that the variant differs from other similar variants. According to the birthplace of the patient the variant is called "Paderborn".

Anemia, Hemolytic, Congenital Nonspherocytic↗
PubMed1977

Changes in activity of malate dehydrogenase and glucosephosphate isomerase in serum of rats exposed chronically to inorganic mercury and its aryl and alkyl compounds.

In course of prolonged exposure [14 weeks] to various mercury compounds [MetHg - a fluid seed-dressing preparation 0,8. Phenyl and Ethyl chlorides and HgC1(2) in doses corresponding to 5% of DL(50)[3 times weekly], enhanced levels of activity of malate dehydrogenase [MDH] and glucosephosphate isomerase [PHI] in blood serum were observed. After 7 weeks of exposure about fourfold increase of MDH and 2-3-fold enhancement of PHI activities were found relative to controls. After 14 weeks of exposure in livers of rats, given MetHg and EtHg, organic mercury was found at concentrations of 28.8 and 4 microng/g tissue, respectively. Inorganic mercury in liver was found in animals given all coumpounds and concentrations were in the range of 1,2 - 4,7 microng/g tissue.

Animals↗
PubMed1975

A new variant of glucosephosphate isomerase deficiency (GPI-Utrecht).

A new case of glucosephosphate isomerase deficiency is described in a Dutch family. The activity of the enzyme was decreased to 20-25% of the normal value. Characterization of the defect enzyme showed a pronounced thermolability. Heating of the enzyme at 45 degrees C showed a loss of activity of 90% after one hour. The pH-optimum and the electrophoretic migration were normal. The Km-value for F-6-P, the Ki for the competitive inhibitors 2,3-DPG and 6-PG were in the normal range. The variant described here differs from all known variants. Therefore we propose to give to this new variant the name of GPI-Utrecht.

Anemia, Hemolytic, Congenital↗
PubMed1977

A new variant of glucosephosphate isomerase deficiency: GPI-Kortrijk.

A new case of glucosephosphate isomerase deficiency in a Belgian family is described. The activity of the enzyme was decreased to about 25-30% of the normal value. Characterization of the defect enzyme showed a decreased thermostability. Heating of the enzyme at 45 degrees C showed a loss of activity of 50% after 90 min. The pH-optimum and the KM-value for fructose 6-phosphate were normal. The electrophoretic pattern showed a faster migration. The variant described here differs from all known variants. Therefore we propose to give to this new variant the name GPI-Kortrijk.

Anemia, Hemolytic, Congenital Nonspherocytic↗
PubMed1978

A preparative method for the isolation of genetic variant forms of glucosephosphate isomerase and a study of five variants.

A method has been developed for the rapid, quantitative separation of normal and abnormal glucosephosphate isomerase allozymes from individuals heterozygous for genetic variant forms of the enzyme. The method utilizes a substrate gradient elution of the enzyme from carboxymethyl Biogel and is far superior in terms of resolution and recovery to methods based on electrophoresis and isoelectric focusing. Five different genetic variant forms of the enzyme were isolated and subjected to a systematic comparison of their physical, catalytic and stability properties. While the physical and catalytic properties of most of the variants were similar, clear differences in the stability of the allozymes were apparent. In order to detect mutations affecting the stability, a series of different stability tests are required.

Genetic Variation↗
PubMed1979

A deletion mutation in glucosephosphate isomerase (GPI Denton).

A new genetic variant form of glucosephosphate isomerase has been found in a family heterozygous for the mutant allele. The mutant enzyme, unlike other phenotypic variants, does not appear to be the result of a single amino acid replacement. The allozyme exhibits an isoelectric point of 5.7 and is thus much more acidic than the normal enzyme (pI = 9.3). The allozyme has been isolated from placenta and separated from the normal homodimer and heterodimer by isoelectric focusing. The enzyme exhibits normal Km and Ki values for the substrates and competitive inhibitors. The allozyme exhibits a normal pH optimum and thermal stability. However, the molecular specific activity of the variant enzyme as quantitated by radioimmunoassay is significantly lower than normal. Analytical gel filtration revealed that the molecular weight of the weight of the enzyme is significantly lower than the normal enzyme. These data thus suggest that the phenotype is unlike any previously reported and is due to a deletion mutation.

Alleles↗
PubMedDate not supplied

Polymorphism at the glucosephosphate isomerase locus in the dog.

A polymorphism of the enzyme glucosephosphate isomerase (GPI) in canine red blood cells is reported. This polymorphism was detected by horizontal starch gel electrophoresis utilizing a tris-EDTA-borate buffer system of pH 8.0. Four out of 92 dogs examined appeared to be heterozygous at this locus.

Animals↗
PubMed1977

Decreased deformability of erythrocytes in haemolytic anaemia associated with glucosephosphate isomerase deficiency.

Deformability of erythrocytes from four patients with different types of glucosephosphate isomerase (D-glucose-6-phosphate ketoisomerase, GPI) deficiency has been determined by cell filtration. Young as well as whole erythrocyte populations had a markedly increased rigidity and an abnormally strong attachment of haemoglobin to the inner surface of isolated membranes. Acidic environment may enhance membran rigidity in vitro and also during passage of the erythrocytes through the spleen. The decrease of deformability at a pH of 6.8 was most pronounced in the splenectomized patients, and likewise in erythrocytes from the splenic artery, which were obtained from one patient during splenectomy. It is suggested that the metabolic environment of the spleen, with its low pH, impairs the deformability of GPI-deficient erythrocytes and predisposes them to splenic sequestration. The clinical improvement of all patients following splenectomy which is accompanied by an increase of the erythrocyte survival time and by unchanged reticulocyte counts, is in accordance with this view.

Adult↗
PubMed1977

Haemolytic anaemia associated with glucosephosphate isomerase (GPI) deficiency in a Black South African child.

Haemolytic anaemia in a Black South African child was found to be associated with reduced glucosephosphate isomerase activity in the red cells. Apart from the haemolytic anaemia, there was no other clinical evidence of dysfunction. Family studies pointed to an autosomal recessive mode of inheritance, with the symptomatic homozygous propositus having a marked enzyme deficiency and the asymptomatic heterozygotes showing intermediate levels of activity. Biochemical characterization showed that, apart from being thermolabile, the electrophoretic mobility and the kinetic properites of the variant enzyme were similar to those of the normal wild type.

Anemia, Hemolytic↗
PubMed1978

A new variant of glucosephosphate isomerase deficiency with mild haemolytic anemia (GPI-MYTHO).

A new case of glucosephosphate isomerase deficiency with mild haemolytic anaemia was observed in a 6-year-old girl. Deficient enzyme was characterized by a profoundly decreased activity in the red cells, a normal electrophoretic phenotype, normal isoelectric point, normal optimum pH, a molecular instability and a clearly decreased Michaelis constant for fructose-6-phosphate. Propositus was double heterozygote for a 'silent gene' inherited from the mother and an abnormal enzyme from the father. Because this abnormal enzyme has undescribed characteristics, it responds to a new variant for which we propose the name GPI-MYTHO.

Anemia, Hemolytic↗