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At least 235 records · Page 13Linked to original sources
PubMed1988

[Fatal consequences of fructose infusion in undiagnosed fructose intolerance].

A 13-year-old girl with previously undiagnosed fructose intolerance was operated on for acute appendicitis. Postoperatively she received several infusions containing fructose or sorbitol. Haematemesis occurred on the fourth postoperative day, as well as tarry stools and jaundice. Blood sugar was 2 mg/100 ml, Quick test 3%, liver enzymes were markedly elevated, serum bilirubin was over 9 mg/100 ml, and there was a metabolic acidosis. Despite intensive treatment, including haemodialysis and plasmapheresis, she died on the 11th postoperative day.

Adolescent↗
PubMed1992

Effect of dietary excess-histidine on fructose 1,6-bisphosphatase and 6-phosphofructokinase activities, and activation of fructose 1,6-bisphosphatase by basic amino acids in rat liver.

1. Dietary excess histidine caused an increase in the total activity of fructose 1,6-bisphosphatase, and a decrease in 6-phosphofructokinase in the liver. 2. The hepatic concentrations of free histidine and lysine were higher in rats fed a histidine-excess diet. 3. The addition of histidine, lysine or arginine to the assay mixture for fructose 1,6-bisphosphatase resulted in a significant increase in its activity. The 6-phosphofructokinase activity in the liver was not enhanced by the addition of histidine to the assay mixture.

Amino Acids↗
PubMed1985

The rate of substrate cycling between fructose 6-phosphate and fructose 1,6-bisphosphate in skeletal muscle from cold-exposed, hyperthyroid or acutely exercised rats.

The effects of cold-exposure, the hyperthyroid state and a single exercise bout in vivo on the maximal enzyme activities of 6-phosphofructokinase and fructose-1,6-bisphosphatase in vastus lateralis muscle and the rates of fructose 6-phosphate/fructose 1,6-bisphosphate cycling measured in epitrochlearis muscle in vitro were investigated. In all cases significant changes in substrate cycling rates were observed, whether in the absence of added hormones in vitro (acute exercise), or when stimulated by insulin plus adrenaline (cold-exposure), or with respect to the catecholamine-sensitivity of the cycling rate (the hyperthyroid state).

Animals↗
PubMed1991

Crystal structure of the neutral form of fructose-1,6-bisphosphatase complexed with the product fructose 6-phosphate at 2.1-A resolution.

The crystal structure of fructose-1,6-bisphosphatase (EC 3.1.3.11) complexed with the product fructose 6-phosphate (F6P) has been refined at 2.1-A resolution to an R factor of 0.177 with root-mean-square deviations of 0.014 A and 2.9 degrees from the ideal geometries of bond lengths and bond angles, respectively. The secondary structures but not the trace of the unligated enzyme have been slightly revised in the F6P complex at this higher resolution. Helix H4 in the unligated structure has been refined to a helix-like coil, and two very short 3(10) helices have been found, one in H4 and one in H5. F6P at 10 mM concentration in the absence of divalent metals in our study shows major binding at the active site and minor binding at the AMP site. The major site has almost equal full occupancy in the C1 and C2 chains of the crystallographic asymmetric unit, while the minor site shows occupancy only in the C1 chain at about 50%. The electron density in both (2Fo - Fc) and (Fo - Fc) maps calculated by omitting F6P slightly favors the beta anomer of D-F6P over the alpha anomer. Possible functions of the active-site residues are discussed, and candidates are suggested for site-directed mutagenesis.

Adenosine Monophosphate↗
PubMed1984

Isolation of a novel protein involved in the transport of fructose by an inducible phosphoenolpyruvate fructose phosphotransferase system in Streptococcus mutans.

Fructose transport in Streptococcus mutans LG-1 is mediated by at least two distinct phosphoenolpyruvate fructose phosphotransferase systems. One system is constitutive and consists of membrane components enzyme II as well as enzyme I and heat-stable protein. The other system is inducible and requires, in addition to enzyme I and heat-stable protein, a soluble substrate-specific protein for catalytic activity. This protein factor, designated IIIfru, was purified by DEAE-cellulose chromatography, hydroxylapatite chromatography, molecular sieving on Sephadex G-75, and preparative electrophoresis. The purified preparation showed only one protein band, with a molecular weight of 12,600, on sodium dodecyl sulfate-urea-polyacrylamide gel electrophoresis, on gel electrophoresis with the discontinuous buffer Tris-glycine, and after electrofocusing in gel (pI congruent to 3.7). The molecular weight of the native protein determined by gel filtration at 4 degrees C was 51,000. Immunodiffusion experiments performed with immunoglobulins prepared against the purified IIIfru from S. mutans LG-1 suggested that other S. mutans strains possessed a IIIfru. No precipitin bands, however, were detected with extracts from S. salivarius, S. sanguis, S. lactis, S. faecalis, Staphylococcus aureus, Bacillus subtilis, Lactobacillus casei, and Escherichia coli.

Biological Transport, Active↗
PubMed1991

Evaluation of cycloserine-cefoxitin-fructose agar and cycloserine-cefoxitin-fructose broth for recovery of Clostridium difficile from environmental sites.

Cycloserine-cefoxitin-fructose agar (CCFA) and cycloserine-cefoxitin-fructose broth (CCFB) containing either 500 or 250 micrograms of cycloserine per ml were compared for efficacy in the isolation of Clostridium difficile from hospital ward environmental sites. A RODAC imprint technique was used to inoculate prereduced CCFA. Moistened swabs were used to inoculate prereduced CCFB from environmental sites immediately adjacent to the RODAC sample sites. CCFA (6% positive) was significantly more sensitive than CCFB (3% positive; P less than 0.005), regardless of the cycloserine concentration. When the CCFA cycloserine concentration was decreased from 500 to 250 micrograms/ml, the overall rate of positive cultures rose from 4 to 17%. Medium containing 500 micrograms of cycloserine per ml may be too inhibitory to isolate many moderately sensitive strains of C. difficile from environmental sites. Regardless of the cycloserine concentration, the CCFA RODAC imprint technique is superior to the CCFB method.

Agar↗
PubMed1996

Inhibition of phosphomannose isomerase by fructose 1-phosphate: an explanation for defective N-glycosylation in hereditary fructose intolerance.

Isoelectrofocusing of serum sialotransferrins from patients with untreated hereditary fructose intolerance (HFI) shows a cathodal shift similar to that in carbohydrate-deficient glycoprotein (CDG) syndrome type I and in untreated galactosemia. This report is on serum lysosomal enzyme abnormalities in untreated HFI that are identical to those found in CDG syndrome type I but different from those in untreated galactosemia. CDG syndrome type I is due to phosphomannomutase deficiency, a defect in the early glycosylation pathway. It was found that fructose 1-phosphate is a potent competitive inhibitor (Ki congruent to 40 microM) of phosphomannose isomerase (EC 5.3.1.8), the first enzyme of the N-glycosylation pathway thus explaining the N-glycosylation disturbances in HFI.

Animals↗
PubMed1988

The inhibition of fructose 1,6-bisphosphatase by fructose 2,6-bisphosphate is enhanced by EDTA and diminished by zinc(II).

The sensitivity of the Mg(II)-dependent activity of rabbit liver fructose 1,6-bisphosphatase (FBPase, EC 3.1.3.11) to inhibition by fructose 2,6-bisphosphate (Fru-2,6-P2) was enhanced by EDTA and diminished to negligible levels by 0.5-2 microM Zn(II) added as another FBPase inhibitor. Fru-2,6-P2 was more efficient in the presence of the synergistic effector AMP: still, the Fru-2,6-P2 concentration inhibiting 50% changed from 3 microM (with EDTA) to higher than 50 microM (with Zn(II]. On the other hand, the Zn(II)-dependent FBPase activity was inhibited by Fru-2,6-P2 to a much lesser extent than the Mg(II)-dependent activity.

Adenosine Monophosphate↗
PubMed1987

Induction of DNA repair in HeLa S3 carcinoma cells by the N-nitroso derivatives of 1-(N-L-tryptophan)-1-deoxy-D-fructose and 1-(5-hydroxytryptamino)-1-deoxy-D-fructose.

HeLa S3 cells, when incubated at 37 degrees C with the N-nitroso derivative of the Amadori compounds 1-(N-L-tryptophan)-1-deoxy-D-fructose (FRU-TRP) or 1-(5-hydroxytryptamino)-1-deoxy-D-fructose (FRU-SEROT) in the presence of a six-fold molar excess of sodium nitrite, exhibit increased intracellular DNA synthesis. Sodium nitrite alone, at identical levels, elicits a similar response, albeit to a much lesser degree. No response whatsoever is produced when the cells are incubated with the parent Amadori compounds. The observed stimulation of DNA replication is DNA repair. Two major routes are suggested by which nitrosated FRU-TRP (NO-FRU-TRP) and nitrosated FRU-SEROT (NO-FRU-SEROT) could damage intracellular DNA.

DNA Repair↗
PubMedDate not supplied

[Level of fructose-2,6-bisphosphate and activity of fructose-1,6-bisphosphatase in hepatocyte suspensions in streptozotocin diabetes].

Content of fructose-2,6-bisphosphate was drastically decreased (about 5-fold) in hepatocyte suspension obtained from rats with streptozotocin-induced diabetes, as compared with that of control animals. At the same time, activity of fructose-1,6-bisphosphatase was increased 2-fold in these hepatocytes. Incubation mixture of the hepatocytes from the diabetes impaired animals contained only low amounts of lactate.

Animals↗
PubMed1994

Molecular cloning and tissue specific expression of fructose 6-phosphate,2-kinase:fructose 2,6-bisphosphatase of rat brain.

A cDNA clone (3591 base pairs) encoding an isozyme of Fructose 6-phosphate, 2-kinase:Fructose 2,6-bisphosphatase was isolated from a rat brain cDNA library. The 5' sequence of this clone (1241 base pairs) was identical to that of the heart type isozyme cDNA (except for 7 base pair mismatches), but the 3' nucleotide sequence (2024 base pairs) was completely different. Its deduced amino acid sequence showed that the enzyme lacked a regulatory domain which contained phosphorylation sites for protein kinase A and C. The results of Northern blotting and polymerase chain reaction demonstrated that the mRNA, 7.4 kilobases long, was expressed also in heart, testis, liver, and skeletal muscle.

Alternative Splicing↗
PubMed1988

Sensitivity of fructose-1,6-biphosphatase from yeast, liver and skeletal muscle to fructose-2,6-biphosphate and 5'-adenosine monophosphate.

As a prerequisite for future studies on the possible effect of sulphite, an anti-microbial agent, on gluconeogenesis in yeast, a comparative study of fructose-1,6-bisphosphatase (FBPase), a key enzyme of gluconeogenesis, from yeast, liver and skeletal muscle is reported. In contrast to FBPase from yeast or liver, FBPase from skeletal muscle is approximately 1000-fold more sensitive to inhibition by 5' adenosine monophosphate and 30 to 250-fold less sensitive to inhibition by fructose-2,6-bisphosphate. The kinetic properties of the FBPases, determined by the ratios R(Mg2+/Mn2+) and R (pH 7/9) of the enzyme activities, measured at 10 mM Mg2+ and 2 mM Mn2+ and at pH 7.0 and 9.0, respectively, show a drastic difference between the skeletal muscle and the yeast or liver enzymes. The data support the idea that the enzymes from yeast and liver function in gluconeogenesis, whereas the enzyme from skeletal muscle is involved in other biological functions.

Adenosine Monophosphate↗
PubMed1989

Localization of fructose 6-P,2-kinase: fructose 2,6-bisphosphatase to human chromosome X.

The gene encoding human liver fructose 6-P,2-kinase: fructose 2,6-bisphosphatase has been assigned to human chromosome X by Southern analysis of a panel of human-rodent somatic cell hybrid DNAs with a cDNA for this gene. A simple two-allele restriction fragment length polymorphism was found with the Fru-6-P,2-kinase:Fru-2,6-bisphosphatase probe; this will allow further localization of this gene by genetic linkage analysis.

Animals↗
PubMed1991

Characterization of two isozymic forms of heart fructose 6-phosphate, 2-kinase:fructose 2,6-bisphosphatase.

Occurrence of two isozymic forms of fructose 6-P, 2-kinase: fructose 2,6-bisphosphatase in bovine heart was investigated by transcribing mRNAs and amplifying the cDNAs with polymerase chain reactions. Analysis of the PCR products revealed 1.7 Kb and 1.5 Kb DNAs, and the determination of their nucleotide sequences showed that these DNAs are identical except for the lack of 180 base pairs near the 3' of the bovine heart enzyme DNA previously reported (6). This missing nucleotide sequence encodes Asn451-Gln510 and contains the phosphorylation sites for cAMP dependent protein kinase and protein kinase C.

Amino Acid Sequence↗
PubMed1988

Isozymes of fructose 6-phosphate,2-kinase:fructose-2,6-bisphosphatase in rat and bovine heart, liver, and skeletal muscle.

The distribution of Fructose 6-P,2-kinase:Fructose 2,6-bisphosphatase in rat and bovine heart, liver, and skeletal muscle tissues was examined. With DEAE-cellulose chromatography, two peaks (I and II) of Fru 6-P,2-kinase activity were detected in all tissue extracts. Peak I was the predominant form both in rat and bovine heart tissue, while peak II was the major form in liver and skeletal muscle. Antibodies to heart enzyme reacted specifically with peak I, and antibodies to liver enzyme reacted with peak II from both liver and skeletal muscle. All the isozymes were bifunctional. All the tissues examined contained other isozymes in minor amounts.

Animals↗
PubMed1988

Molecular cloning, sequence analysis, and expression of a human liver cDNA coding for fructose-6-P,2-kinase:fructose-2,6-bisphosphatase.

A cDNA coding for 378 amino acids from the C-terminus of the human liver bifunctional enzyme, Fructose-6-phosphate,2-kinase:Fructose-2,6-bisphosphatase was isolated, sequenced, and expressed in E. coli K38. The expressed protein, identified by specific immunoassay, showed Fru 2,6-bisphosphatase activity but no Fru 6-P,2-kinase activity, demonstrating directly that the Fru 2,6-bisphosphatase activity resides in the C-terminal region. The Km for Fru 2,6-P2 was 4.3 microM. Fru 6-P was a noncompetitive inhibitor (Ki = 2.9 microM), and formed a phosphorylated intermediate when incubated with Fru 2,6[2-32P]P2. The subunit Mr of the enzyme was 36,600, and the active enzyme showed Mr = 37,000 by gel filtration.

Base Sequence↗
PubMed1984

Increase of intraerythrocytic fructose-1,6-diphosphate after incubation of whole human blood with fructose-1,6-diphosphate.

The incubation of whole blood with fructose-1,6-diphosphate (FDP) entails a statistically significant increase of intraerythrocytic FDP together with a decrease of blood glucose. The increase is not significant when equimolar amounts of fructose plus twice molar phosphate are used. The effect of FDP is decreased in the presence of an excess of oxygen. FDP added to the whole blood is removed from plasma by the activity of plasma enzymes and by the presence of blood cells as well. No specific interaction of FDP with plasma proteins seems to occur and the effects of FDP addition last longer than is compatible with the presence of FDP in the plasma.

Adolescent↗