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Expression of the human adenylate kinase isozymes, phosphopyruvate hydratase, 6-phosphogluconate dehydrogenase, and phosphoglucomutase-1 in man-rodent somatic cell hybrids.

The expression of the adenylate kinase isozymes and of phosphopyruvate hydratase was studied in man-mouse and man-hamster hybrid clones. Concordant segregation of the loci coding for AK-2 and PPH was observed in 54 of 55 primary hybrid clones, and these loci were demonstrated to be synthetic with the loci specifying PGM-1 and PGD. The pattern of expression of the four enzymes in discordant clone suggests the gene order 1pter-(PGD, PPH)-AK-2-PGM-1-centromere. In addition, AK-1 was found to be expressed independently of AK-2.

Adenylate Kinase

Location of gluconeogenesis from phosphoenolpyruvate in cotyledons of Cucurbita pepo.

1. The aim of this work was to discover the location of the enzymes that convert phosphoenolpyruvate to fructose 6-phosphate during gluconeogenesis in fatty seeds. Cotyledons of 5-day-old dark-grown seedlings of marrow (Cucurbita pepo) were used as experimental material. 2. Cotyledons were separated into palisade and mesophyll tissue. Extracts of the two tissues had comparable activities of gluconeogenic enzymes. 3. Extracts of cotyledons were fractionated by density gradient centrifugation to yeild mitochondria and glyoxysomes, and by gel filtration to yield proplastids. The isolated organelles retained their characteristic ultrastructure and appreciable amounts of marker enzymes. The proportions of the total activities of phosphoglyceromutase and fructose-1, 6-diphosphatase recovered in the mitochondrial and glyoxysomal preparations were insignificant. The same was true for the activities of phosphoglyceromutase and phosphopyruvate hydratase found in the proplastid preparations. 4. Extracts of a number of other gluconeigenic plant tissues were centrifuged at 2500 times g to yield particulate preparations. None of these preparations contained a significant proportion of the total activity of phosphoglyceromutase. 5. It is suggested that gluconeogenesis from phosphoenolpyruvate in plants occurs in the cytoplasm.

Cell Fractionation

Setaria cervi: enzymes of glycolysis and PEP-succinate pathway.

Setaria cervi, the filarial parasite inhabiting the Indian water buffalo (Bubalus bubalis Linn.) contained almost all the enzymes involved in glycogen degradation. Significant activities of glycogen phosphorylase, glucokinase, phosphoglucomutase, phosphoglucose isomerase, phosphofructokinase, FDP-aldolase, glyceraldehyde-3-phosphate dehydrogenase, phosphopyruvate hydratase, pyruvate kinase, lactate dehydrogenase glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase were detected in cell-free extracts of whole worms. The presence of PEP-carboxykinase, malate dehydrogenase, fumarase and fumarate reductase revealed the functioning of the PEP-succinate pathway in addition to phosphorylating glycolysis and pentose phosphate pathway in the parasite. Excepting fumarate reductase all other enzymes were localized in the particulate-free cytosol fraction, although small amounts of glycogen phosphorylase, aldolase and lactate dehydrogenase were also detected in the mitochondrial fraction.

Animals

Purification and characterization of phosphoglycerate mutase from methanol-grown Hyphomicrobium X and Pseudomonas AM1.

Phosphoglycerate mutase has been purified from methanol-grown Hyphomicrobium X and Pseudomonas AMI by acid precipitation, heat treatment, ammonium sulphate fractionation, Sephadex G-50 gel filtration and DEAE-cellulose column chromatography. The purification attained using the Hyphomicrobium X extract was 72-fold, and using the Pseudomonas AMI extract, 140-fold. The enzyme purity, as shown by analytical polyacrylamide gel electrophoresis, was 50% from Hyphomicrobium X and 40% from Pseudomonas AMI. The enzyme activity was associated with one band. The purified preparations did not contain detectable amounts of phosphoglycerate kinase, phosphopyruvate hydratase, phosphoglycerate dehydrogenase or glycerate kinase activity. The molecular weight of the enzymic preparation was 32000 +/- 3000. The enzyme from both organisms was stable at low temperatures and, in the presence of 2,3-diphosphoglyceric acid, could withstand exposure to high temperatures. The enzyme from Pseudomonas AMI has a broad pH optimum at 7-0 to 7-6 whilst the enzyme from Hyphomicrobium X has an optimal activity at pH 7-3. The cofactor 2,3-diphosphoglyceric acid was required for maximum enzyme activity and high concentrations of 2-phosphoglyceric acid were inhibitory. The Km values for the Hyphomicrobium X enzyme were: 3-phosphoglyceric acid, 6-0 X 10(-3) M: 2-phosphoglyceric acid, 6-9 X 10(-4) M; 2,3-diphosphoglyceric acid, 8-0 X 10(-6) M; and for the Pseudomonas AMI ENzyme: 3-4 X 10(-3) M, 3-7 X 10(-4) M and 10 X 10(-6) M respectively. The equilibrium constant for the reaction was 11-3 +/- 2-5 in the direction of 2-phosphoglyceric acid to 3-phosphoglyceric acid and 0-09 +/- 0-02 in the reverse direction. The standard free energy for the reaction proceeding from 2-phosphoglyceric acid to 3-phosphoglyceric acid was -5-84 kJ mol(-1) and in the reverse direction +5-81 kJ mol(-1).

Bacteria

Regional assignment of seven genes on chromosome 1 of man by use of man-Chinese hamster somatic cell hybrids. I. Results obtained after hybridization of human cells carrying reciprocal translocations involving chromosome 1.

Regional localization studies of genes coding for human PGD, PPH1, PGM1, UGPP, GuK1, Pep-C, and FH, which have been assigned to chromosome 1, were performed with man-Chinese hamster somatic cell hybrids, Informative hybrids that retained fragments of the human chromosome 1 were produced by fusion of hamster cells with human cells carrying reciprocal translocations involving chromosome 1. Analysis of the hybrids that retained one of the translocation chromosomes or de novo rearrangements involving the human 1 revealed the following gene positions: PGD and PPH1 in 1pter leads to 1p32, PGM1 in 1p32 leads to 1p22, UGPP and GuK1 in 1q21 leads to 1q42, FH in 1qter leads to 1q42, and Pep-C probably in 1q42.

Animals

Description of a human papillary thyroid carcinoma cell line. Morphologic study and expression of tumoral markers.

BACKGROUND: The establishment of cell lines from thyroid carcinomas can provide an in vitro model of oncogenesis. B-CPAP is a new cell line that has been obtained from a differentiated papillary thyroid carcinoma. The data presented give a broader characterization and expression of tumoral markers of this cell line and identify the differentiated functions that are preserved. METHODS: An ultrastructural study was performed to confirm the thyroid nature of the new cell line. The cellular markers (thyroglobulin, S100, neuron-specific enolase [NSE]) and the oncogenes (mutated p53, H-ras, c-myc, PTC, trk) were studied by immunohistochemistry, Southern blot, or in situ hybridization. RESULTS: The cells were of a differentiated ultrastructural thyroid type. All of the cells proved immunoreactive with antibodies specific to thyroglobulin, S100 proteins, NSE, and mutant p53 protein. Mutations of H-ras, PTC, and trk were not observed. The c-myc gene was not amplified. CONCLUSIONS: The cell line described in these data provides a suitable model for the study of thyroid carcinogenesis, given that the cells present thyroid characteristics, and metabolic disorders not previously found in such cell lines. In addition, the coexpression of S100 proteins and mutant p53 proteins in the cells should permit the study of the interaction between these two proteins.

Aged

Isozyme patterns in erythrocytes from human fetuses.

Starch gel electrophoretic patterns of 26 enzymes (corresponding to 36 gene loci) were examined in hemolysates of erythrocytes from 11 first-trimester and mid-trimester human fetuses (65-138 gestation days). The zymograms of 16 enzymes were identical in fetal and control adult red cells. Six enzymes (enolase, guanylate kinase, lactate dehydrogenase, nucleoside phosphorylase, phosphofructokinase, hexokinase) showed differences in the staining intensity of certain isozyme zones as compared with the controls. Also, the fetal red cell zymograms, in contrast to those of adults, contained the mitochondrial forms of isocitric dehydrogenase and glutamic oxaloacetic transaminase as well as more definite zones of phosphoglucomutase-3. Finally, some of the isozymes of uridine diphosphate kinase in the fetal cells had slightly retarded mobility. These observed differences between fetal and adult red cells could reflect the expression of a different program of protein synthesis in red cells of the fetuses or the epigenetic modifications of isozymes in immature red cells.

Electrophoresis, Starch Gel

Glyceraldehyde 3-p dehydrogenase, glycerate 3-P kinase and enolase mutants of Escherichia coli: genetic studies.

The genetic loci for two enzymes of glycolysis have been established by transductional crosses. The eno locus, likely to be the structural gene for enolase maps in the 52-minute region of the Escherichia coli chromosome. A structural determinant for glycerate 3-P kinase (pgk) is located near serA. The map order is speB-pgk-serA-lysA-argA-eno-cysC. In the 35-minute region maps a locus affecting the structure of glyceraldehyde 3-P dehydrogenase.

Chromosome Mapping

Enzymatic analysis of the pathways of glucose catabolism and gluconeogenesis in Pseudomonas citronellolis.

Extracts of Pseudomonas citronellolis cells grown on glucose or gluconate possessed all the enzymes of the Entner-Doudoroff pathway. Gluconokinase and either or both 6-phosphogluconate dehydratase and KDPG aldolase were induced by growth on these substrates. Glucose and gluconate dehydrogenases and 6-phosphofructokinase were not detected. Thus catabolism of glucose proceeds via an inducible Entner-Doudoroff pathway. Metabolism of glyceraldehyde 3-phosphate apparently proceeded via glyceraldehyde 3-phosphate dehydrogenase, phosphoglycerate kinase, phosphoglycerate mutase, enolase and pyruvate kinase. These same enzymes plus triose phosphate isomerase were present in lactate-grown cells indicating that synthesis of triose phosphates from gluconeogenic substrates also occurs via this pathway. Extracts of lactate grown-cells possessed fructose diphosphatase and phosphohexoisomerase but apparently lacked fructose diphosphate aldolase thus indicating either the presence of an aldolase with unusual properties or requirements or an alternative pathway for the conversion of triose phosphate to fructose disphosphate. Cells contained two species of glyceraldehyde 3-phosphate dehydrogenase, one an NAD-dependent enzyme which predominated when the organism was grown on glycolytic substrates and the other, an NADP-dependent enzyme which predominated when the organism was grown on gluconeogenic substrates.

Fructose-Bisphosphatase

Immunofluorescent localization of glycogenolytic and glycolytic enzyme proteins and of malate dehydrogenase isozymes in cross-striated skeletal muscle and heart of the rabbit.

Specific antisera against glycogen phosphorylase, phosphofructokinase, aldolase, glyceraldehyde-phosphate dehydrogenase, enolase, lactate dehydrogenase, cytosolic and mitochondrial malate dehydrogenase from rabbit muscle were obtained from sheep. The gamma-globulins were used for indirect immunofluorescent localization of the respective enzymes in rabbit skeletal muscle and heart. In stretched skeletal muscle a cross-striation like distribution was observed for all enzymes studied. In the case of mitochondrial malate dehydrogenase this pattern is due to the staining of I-band mitochondria. In cross-sections, an intense staining of the sarcolemma and of subsarcolemmal mitochondria was observed. Comparative analyses with polarized light revealed that the cytosolic enzymes under study are distributed in the relaxed muscle fibre predominantly within the isotropic zones. The same distribution holds also for heart. In contracting muscle a decrease in cross-striated fluorescence and a faint staining of the interfibrillar spaces suggests a location also within the interfibrillar space.

Animals

[Enzyme deficiencies in glycolysis and nucleotide metabolism of red blood cells in nonspherocytic hemolytic anemia (author's transl)].

The detection of enzyme deficiencies in glycolytic and nucleotide metabolism of human red blood cells has enriched the pathophysiological knowledge on the origin of nonspherocytic hemolytic anemias (NSHA). So far for 11 of 13 glycolytic enzymes deficiencies have been described which are connected with alterations of biochemical enzymatic properties. The most frequent enzyme deficiencies are those of GPI and PK. By performance of special electrophoretic techniques genetic studies allow the demonstration of homozygote and double heterozygote defect carriers. Up to now only adenylate kinase and pyrimidine 5' nucleotidase deficiencies have been detected as genetically determined in altered nucleotide metabolism. The metabolic alterations of several enzymopathies have been characterized so well, that the pathophysiological relations between enzyme deficiency and NSHA probably have been found to be a sufficient explanation.

Adenosine Triphosphatases