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)

DNA polymerase [EC 2.7.7.7] activities present in hypotonic extract from rat ascites hepatoma AH130 cells were eluted in three separable peaks on DEAE-cellulose column chromatography. Peak I activity had an alkaline pH optimum, and was relatively resistant to SH-blocking reagents and salt concentration. These properties of DEAE peak I are typical of low molecular weight DNA polymerase. DEAE peak II and peak III activities possessed properties corresponding to high molecular weight (6-8 S) polymerase; they showed maximal activity at neutral pH, and were sensitive to SH-blocking reagents and salt. No low molecular weight polymerase activity was released from DEAE peak II or peak III by salt treatment, though partial conversion from DEAE peak II to peak III was observed on the same treatment.
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PMID:Studies on the molecular species of DNA polymerase extracted from rat ascites hepatoma cells. 0 55

Mouse alpha-foetoprotein (alphaFP) was isolated from H4 hepatoma tissue using Con A-Sepharose salt gradient ion exchange chromatography and ampholyte displacement chromatography, the latter being a new method for a sharp separation of proteins based on their different isoelectric point. The purity of the alphaFP was demonstrated by (i) the absence of contaminant on sodium dodecyl sulphate polyacrylamide gel electrophetic gels, (ii) Ouchterlony's immunodiffusion against monospecific antimouse alphaFP and the absence of precipitation against a polyvalent antinormal mouse serum, (iii) the production of a monospecific antiserum in a rabbit after injection of the purified antigen, and (iv) immunological unreactivity of the produced antiserum against normal hepatic tissue.
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PMID:Purification of mouse alpha-foetoprotein by ampholyte displacement chromatography. 8 84

Proteinase associated with chromatin isolated from liver and hepatoma of rat is stimulated by salt, and, of the histone fractions, lysine-rich (F1) histone is preferentially degraded by this enzyme at an ionic strength comparable with that found in the nucleus. However, there appears to be no strict relationship between the activity of the proteinase and growth rates of hepatomas. Chromatin isolated from a fast-growing tumour, Ehrlich ascites carcinoma, shows no apparent proteinase activity in the presence of salt.
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PMID:Lack of relationship between activity of chromatin-bound proteinase and cell growth rates. 16 17

Nuclear proteins of rat liver and rat ascites hepatoma were fractionated by extraction in solutions of different salt concentration and analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis. The difference between the electrophorograms of the different fractions of nuclear proteins isolated from liver and from hepatoma was found in the bands which have the same electrophoretic mobility as the main proteins of informofers and are extracted from nuclei at salt concentrations which extract informofers. These changes in the electrophoretic patterns of proteins with the solubility and mobility of the proteins of informofers could be related to the defective processing of heterogeneous nuclear RNA in the hepatoma. In addition the identity of electrophorograms of nuclear proteins isolated from liver and from hepatoma and the identity of most bands in the electrophorograms of nuclear proteins which are soluble in 0.35 M NaCl and chromosomal proteins which are not soluble at this salt concentration support the notion that these nonhistone nuclear proteins which can be identified as the major bands in electrophorograms of chromosomal proteins are not the specific regulators of gene expression.
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PMID:Nuclear proteins of rat liver and of an aminoazo-dye-induced hepatoma. 16 62

A salt-extraction procedure was used to isolate a nucleolar nonhistone protein fraction, containing [32P]phosphoserine, from the nucleoli of Novikoff hepatoma ascites cells. These proteins are similar in amino-acid composition to whole nuclear (chromosomal) nonhistone proteins. DNA-cellulose column chromatography showed that this fraction contains DNA-binding phosphoproteins, some of which will bind only to homologous (Novikoff) nucleolar or nuclear DNA.
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PMID:DNA-cellulose column chromatography of phosphorylated nucleolar nonhistone proteins. 17 59

A group of chromosomal non-histone proteins with affinity for DNA (NP) was isolated from rat liver and Novikoff hepatoma. This fraction, which represents less than 5% of the total chromatin protein content, binds preferentially to unique, double-stranded sequences of fractionated homologous DNA. The interactions are strong at low ionic strength (Km = 6.7 X 10(-9) M) and decrease with rising salt concentration. Complexes of the NP protein fraction with homologous DNA are immunologically tissue-specific. As determined by microcomplement fixation, the NP proteins in Novikoff hepatoma are associated with the transcriptionally active, diffuse fraction of chromatin.
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PMID:Tissue-specific chromosomal non-histone protein interactions with DNA. 17 52

DNA-dependent RNA polymerases (EC 2.7.7.6) were extracted and partially purified form the nuclei of rat ascites hepatoma cells (AH-130) induced by 4-dimethylaminoazobenzene. The patterns of RNA synthesis and the properties of these enzymes were compared with enzymes from the nuclei of rat liver. The specific activity of RNA polymerase in the homogenate from the nuclei of AH-130 cells was the same as normal rat liver nuclei. RNA polymerase was solubilized from the homogenate at high ionic strength and separated into two forms by DEAE-Sephadex column chromatography. Enzymatic characterization showed that these enzymes corresponded to RNA polymerase I and II. RNA polymerase I more effectively transcribed native DNA than denatured DNA at low salt concentration, but at high salt concentration RNA polymerase I effectively transcribed denatured DNA. RNA polymerase II more effectively transcribed denatured DNA. In AH-130 cells the activity of RNA polymerase I was 4 to 5 times higher than RNA polymerase II, and in rat liver the activity of RNA polymerase I was 1.5 to 2 times higher than RNA polymerase II. The activity of RNA polymerase I in AH-130 cells may have increased by induction.
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PMID:A comparative study of DNA-dependent RNA polymerases from rat ascites hepatoma cell nuclei and from rat liver nuclei. 18 Jul 54

The ability of confluent monolayers of H-35 cells, originally obtained from a rat hepatoma, to synthesize prothrombin in response to vitamin K1 (phylloquinone) was studied. As demonstrated by radioimmunoassay, selective barium salt adsorption, and two coagulation assays which discriminate between precursor- and mature-prothrombin, these cells retained their ability to synthesize precursor prothrombin (preprothrombin) in the absence of exogenous phylloquinone (vitamin K). When phylloquinone was added to the medium (100 ng/ml), the existing intracellular concentration of preprothrombin was reduced to 50% within 1 hr after exposure to the vitamin and slowly declined thereafter to approximately 30% of control levels by 36 hr. Concomitant with the rapid loss of intracellular preprothrombin was the appearance of mature prothrombin in the medium. The appearance of prothrombin was biphasic: occurring during the initial 0-6 hr interval, and again at an increased rate during the next 18-24 hr interval. The amount of prothrombin appearing in the medium exceeded by severalfold the amount of precursor mobilized. These data demonstrate that monolayer cultures of H-35 hepatoma cells retain their ability to synthesize preprothrombin and other enzymes, responsible for post-translational modification of prothrombin and its subsequent secretion, under the influence of vitamin K.
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PMID:Vitamin K-dependent synthesis and modification of precursor prothrombin in cultured H-35 hepatoma cells. 18 12

The Novikoff hepatoma DNA polymerase-beta sediments as a 7.3S form in crude extracts but during purification sediments as a 4.1S form (after diethylaminoethyl-Sephadex chromatography) or as a 3.3S form (after DNA-cellulose chromatography). If 0.25 M ammonium sulfate or 0.5 M NaCl is included in the sucrose gradients, the 7.3S form sediments at 3.3 S; after removal of the salt, it sediments again at 7.3 S, indicating the reversibility of the aggregation phenomenon. By careful adjustment of ionic strength in the gradient, four distinct and reproducible forms of the enzyme sedimenting at 7.3, 5.8, 4.1, and 3.3 S can be generated. The isoelectric point of the DNA polymerase also changes during purification; the 7.3S form has a pI of 7.5, while the 4.1S form isoelectrically focuses at a pH of 8.5. During DNA-cellulose chromatography, the Novikoff beta-polymerase is separated from a stimulatory factor designated as Novikoff factor IV. Factor IV is a protein as shown by its sensitivity to protease and resistance to nucleases. It is responsible for converting the 3.3S enzyme to the 4.1S form since the 3.3S homogeneous DNA polymerase-beta sediments at 4.1 S in the presence of factor IV. Factor IV confers stability to the polymerase in low ionic strength buffers as well as stability to heat denaturation. Factor IV has the ability to increase the activity of the 3.3S homogeneous polymerase by about fourfold.
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PMID:Novikoff hepatoma deoxyribonucleic acid polymerase. Identification of a stimulatory protein bound to the beta-polymerase. 19 Oct 73

A substantial portion of the histone phosphorylating activity of bovine thymus chromatin can be isolated by extraction in 0.2 M NaCl. The specificity of this extract for either free histones or washed chromatin substrates was compared. The salt-extracted kinase enzymes favor H2b as the major acceptor when whole free histone is the substrate and H3 when the substrate is intact chromatin. The H3 kinase activity of bovine thymus tissue has been purified free from other detectable histone kinase activities by ammonium sulfate fractionation and is highly specific for H3 histone when assayed either with chromatin or isolated whole histone. The activity is cAMP-independent. Tryptic peptide mapping of the labeled H3 histone reveals a single site of phosphorylation. This site appears to be identical with the major site of metaphase-associated H3 phosphorylation in hepatoma tissue culture cells. No corresponding H3 phosphorylation has been detected in thymus tissue in vivo.
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PMID:An H3 histone-specific kinase isolated from bovine thymus chromatin. 20 51


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