Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0019204 (hepatocellular carcinoma)
 71,386 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The purification to homogeneity of hexokinases B and C from the cytosol of rat Novikoff hepatoma was achieved by a protocol using an initial chromatography on Blue 2-agarose to separate the isoenzymes from each other. After that step each hexokinase was subjected to chromatography on DEAE-cellulose, hydroxyapatite and Sephacryl S-300, followed by re-chromatography on hydroxyapatite. The final preparations of hexokinases B and C had specific activities of 86 and 23.5 units/mg of protein respectively, and gave single bands on electrophoresis under non-denaturing conditions or in SDS/polyacrylamide gels. Mr values of about 100,000 were found for both isoenzymes either by Sephacryl S-300 chromatography or by SDS/polyacrylamide-gel electrophoresis. Values of apparent Km for glucose and ATP of pure hexokinase B were similar to those reported for the enzyme from other sources. The apparent Km value for glucose of hexokinase C was 0.025 mM. Marked inhibition of hexokinase C by glucose concentrations above 0.2 mM was found. The effect was partially relieved by ATP concentrations above 1 mM and was independent of pH. Glucose 6-phosphate was inhibitory, but the Ki value (0.18 mM) is higher than those reported for other animal hexokinases. The amino acid composition of hexokinase C was found to be similar to those reported for hexokinases B and D. Also, an immune serum directed against hexokinase A was able, at low dilutions, to bind hexokinases B and C. An immune serum directed against hexokinase C was able, at low dilutions, to bind hexokinase B and also, but weakly, hexokinase A.
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PMID:Hexokinase isoenzymes from the Novikoff hepatoma. Purification, kinetic and structural characterization, with emphasis on hexokinase C. 359 83

The highly active alcohol dehydrogenase (EC 1.1.1.1) in rat hepatic tumor cells (HTC) was purified 120-fold by chromatography on DEAE-Sepharose and AMP-Agarose to yield an enzyme with a specific activity of 88 mumole/min/mg protein, assayed with 1.7 mM NAD+ and 0.55 M ethanol at pH 9 and 30 degrees C. (By comparison, purified, normal rat liver enzyme has an activity of about 1 unit/mg.) Based on its physical and kinetic properties, we conclude that the HTC isozyme is the same as the enzyme from rat stomach and another rat hepatoma (Cederbaum AI, Pietruszko R, Hempel J, Becker FF, and Rubin E (1975) Arch Biochem Biophys 171:348-360). The kinetics of the HTC enzyme are consistent with the Ordered Bi Bi mechanism. The kinetic constants are generally much larger for the HTC enzyme than for the normal rat liver enzyme. The Michaelis constants for ethanol and acetaldehyde (Kb = 1100 mM, Kp = 260 mM) are 1000-fold larger, and the constants for NADH are 10 to 50-fold larger. Although the HTC enzyme has low catalytic efficiency (V/Kb) on ethanol, it has much better activity on longer chain alcohols, but no activity on cyclohexanol. The pH dependence of V/Kb with ethanol is unusual in that it appears to be a linear function of pH, increasing with a slope of 0.56. Thus, the active sites of the liver and HTC enzymes may be different, although the HTC enzyme is inactivated by bromoacetate and bipyridine as is found for the liver enzyme. The HTC (stomach) enzyme may function to oxidize high concentrations of ingested ethanol or longer chain alcohols.
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PMID:Characterization of alcohol dehydrogenase from cultured rat hepatoma (HTC) cells. 361 21

PC 12h pheochromocytoma cells were subcutaneously transplanted into rat. We found the transplanted tumors accumulated some fucogangliosides associated with PC 12 cells. These gangliosides were isolated and purified by DEAE-Sephadex A-25 and Iatrobeads column chromatographies. Their structures were determined by fast atom bombardment mass spectrometry, proton nuclear magnetic resonance spectrometry, permethylation study, and sequential degradation using various exoglycosidases and mild acid hydrolysis. Two tumor-associated fucogangliosides were found to possess the blood group B determinant as follows: G6: IV2Fuc alpha, IV3Gal alpha, II3NeuAc, GgOse4Cer; G11: IV2Fuc alpha, IV3Gal alpha, II3 (NeuAc)2, GgOse4Cer. A ganglioside with the similar structure as ganglioside G6 was isolated from rat hepatoma cells (Holmes, E.H., and Hakomori, S-I. (1982) J. Biol. Chem. 257, 7698-7703). However, ganglioside G11 has not previously been reported in the literature. These fucogangliosides reacted with the monoclonal antibody prepared by immunizing mice with PC 12h cells. Other fucogangliosides were also found to accumulate in the transplanted tumor tissues. They were identified as fucosyl-GM1 and fucosyl-GDlb. These fucogangliosides did not react with the monoclonal antibody against PC 12h cells.
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PMID:Characterization of tumor-associated fucogangliosides from PC 12 pheochromocytoma cells. 365 55

Nuclear extracts obtained from normal rat liver and from Morris hepatoma 3924A were fractionated by DEAE-Sephadex chromatography. The fraction eluted with 175 mM (NH4)2SO4 (DE-B), which contains greater than 90% of RNA polymerase I activity, supported accurate transcription of cloned rat rDNA. A similar fraction obtained from the cytosol had all of the factors required for rDNA transcription. However, its transcriptional activity was at most one-sixth that of the corresponding nuclear fraction, as determined by the amount of protein needed to produce a similar quantity of the transcript. Unfractionated nuclear or cytosol preparations did not yield an accurate transcript. Optimal KCl and magnesium concentrations for rDNA transcription were 60 mM and 5-7.5 mM, respectively. The extent of transcriptional activity was in the following order: hepatoma nuclear fraction DE-B greater than whole cell extract derived from rat mammary adenocarcinoma cells much greater than normal liver fraction DE-B. The hepatoma preparation produced at least 10 times the amount of transcript produced by the corresponding liver nuclear preparation. Transcriptional activity was proportional to the levels of RNA polymerase I and to the rate of rRNA synthesis in these tissues.
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PMID:Accurate initiation of rat ribosomal RNA gene transcription using a fractionated nuclear extract from normal liver and a hepatoma. 385 47

DNA methyltransferase (DMase) was purified 700- and 1002-fold from normal rat liver and transplantable hepatocellular carcinoma 252 (THC 252) nuclei, respectively, using a four-step procedure that included chromatography on phosphocellulose, hydroxylapatite, DEAE-Sephacel and gel filtration on AcA 34. The enzymes had identical characteristics: pI = 7.4-7.6; Mr = 280 000 by gel filtration; preference for methylating double-stranded over single-stranded DNA and hemimethylated over unmethylated DNA templates; and apparent km of 10 microM for dinucleotide units in poly(dC-dG) and 0.5 microM for S-adenosylmethionine (SAM). Thermal inactivation profiles and sulfhydryl group alkylation inhibition curves for fraction III produced very similar single-transition curves, suggesting the presence of a single-functional enzyme species that is indistinguishable between normal and tumor tissue. Single-value Michaelis-Menten kinetics were obtained for fraction IV enzymes with respect to the concentration of SAM and dinucleotide units in poly(dC-dG), suggesting the absence of isozymic or multiple forms of DMase in normal and malignant liver tissues.
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PMID:Indistinguishable physical and catalytic properties of DNA methyltransferase from normal rat liver and a transplantable rat hepatocellular carcinoma. 400 74

A non-histone protein was obtained by extraction of nuclei derived from rat liver or thymus or ascites-hepatoma cells with 5% (w/v) HClO(4). Separation from histone F1 was achieved by chromatography on DEAE-cellulose. The purified component P1 was characterized and the formation of complexes with histone F1 and polylysine was studied.
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PMID:The characterization of a non-histone protein isolated from histone F1 preparations. 435 16

The poly(A) tract found in eukaryotic mRNA was used to study methylation in mRNA obtained from Novikoff hepatoma cells. Methyl labeling of RNA was achieved with L-[methyl-(3)H]methionine under conditions that suppress radioactive incorporation into the purine ring. RNA that contains a poly(A) segment was obtained from polysomal RNA by chromatography on oligo(dT)-cellulose. Sucrose density gradient centrifugation of this RNA revealed a pattern expected for mRNA. The composition of the methyl-labeled nucleosides in the RNA was analyzed after complete enzymatic degradation to nucleosides. By use of DEAE-cellulose (borate) chromatography, which separates 2'-O-methylnucleosides from normal and base-methylated nucleosides, about 50% of the radioactivity was recovered in the 2'-O-methylnucleoside fraction and 50% in the base-methylnucleoside fraction. High-speed liquid chromatography (Aminex A-5) of the 2'-O-methylnucleoside fraction produced four peaks coincident with the four 2'-O-methylnucleoside standards. Analysis of the base-methylnucleoside fraction revealed a unique pattern. While ribosomal RNA and tRNA possessed complex base-methylnucleoside patterns, the distribution in mRNA was quite simple, consisting predominantly of N(6)-methyladenosine. These results demonstrate a unique distribution of methylated nucleosides in mRNA. By analogy to ribosomal RNA synthesis, the presence of methylnucleosides in mRNA may reflect a cellular mechanism for the selective processing of certain mRNA sequences.
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PMID:Identification of methylated nucleosides in messenger RNA from Novikoff hepatoma cells. 437 99

A substance capable of promoting tumour cell aggregation was released from rat ascites hepatoma cell (possibly from the cell surface) kept in Hanks' balanced salt solution (free of calcium and magnesium) in the cold, and then partially purified by chromatography with DEAE-Sephadex and gel filtration with Bio-gel. The thermostable substance seemed to be a glycoprotein and its molecular weight was about 72,000 when measured by gel filtration on Sephadex G-200. It had no proteolytic activity. The material was clearly effective for rat ascites hepatoma cells as well as SV40 transformed cells, but less effective for Chang's cells and apparently ineffective for normal rat liver cells and red blood cells. The action of this material was more potent than that of Jack bean concanavalin A when assayed for aggregation of SV40 transformed cells. Its effect was not influenced by concanavalin A inhibitors such as alpha-methyl-D-glucopyranoside, N-acetyl-D-glucosamine and D-glucose.
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PMID:A tumour cell aggregation promoting substance from rat ascites hepatoma cells. 437 63

To investigate the alterations of phosphoseryl/phosphothreonyl-protein phosphatases in neoplastic tissues, the cytosols of rat liver and AH-13, a strain of rat ascites hepatoma, were chromatographed on DEAE-cellulose and the fractions obtained were assayed for protein phosphatase with glycogen synthase D and phosphorylase alpha as phosphoprotein substrates. While the glycogen synthase phosphatase and phosphorylase phosphatase activities of liver cytosol were largely due to phosphatases IA and II, respectively, as previously reported, these phosphatases were absent or present in only small amounts in AH-13 cytosol, whose glycogen synthase phosphatase and phosphorylase phosphatase activities were due almost wholly to a novel protein phosphatase that appeared to be absent in liver. This phosphatase, termed phosphatase H, was purified further by aminohexyl-Sepharose-4B and Sephadex G-200 chromatography without altering its glycogen synthase D/phosphorylase alpha activity ratio. Purified phosphatase H required Mg2+ or Mn2+ for activity and had a molecular weight of about 330,000. It displayed a substrate specificity broader than that of either phosphatase IA or II.
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PMID:Cytosolic protein phosphatases of rat ascites hepatoma AH-13 as compared with those of rat liver: isolation and characterization of a novel protein phosphatase. 608 36

Ferritin was extracted from human hepatocellular carcinoma tissue and purified using column chromatography, gradient gel electrophoresis and cadmium sulphate crystallization. DEAE cellulose chromatography showed a difference between hepatoma and normal liver ferritin, indicative of a more acidic isoferritin profile in the tumour. Column-purified and crystalline ferritin and that remaining in the mother-liquor after crystallization was subjected to isoelectric focusing. Hepatoma ferritin showed higher concentrations of acidic isoferritins than liver ferritin. This was most obvious with mother-liquor ferritin, as crystallization tended to select out more basic isoferritins. Subunit analysis of hepatoma and liver ferritin showed a higher proportion of heavy subunits in the tumour ferritin, in keeping with the presence of acidic isoferritins. An antibody against hepatoma mother-liquor ferritin was raised in rabbits. However, hepatoma ferritin proved to be antigenically identical with normal liver ferritin, and we were thus unable to develop a specific radioimmunoassay for hepatoma ferritin.
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PMID:Isolation of ferritin from human hepatocellular carcinoma. 609 60


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