Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

---

Query: EC:2.4.2.8 (hypoxanthine-guanine phosphoribosyltransferase)
2,527 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Human erythrocyte lysate proteins were resolved into over 250 discrete spots by two-dimensional electrophoresis using isoelectric focusing in the first dimension and electrophoresis in the presence of sodium dodecyl sulfate, (SDS) in the second. The overwhelming excess of hemoglobin has made such analyses difficult in the past. However, with the ISO-DALT two-dimensional electrophoresis system, large numbers of red cell proteins can be mapped in the presence of hemoglobin. When hemoglobin and several other major proteins are removed by adsorption to DEAE-cellulose, additional minor components are seen, giving a total of over 275. With the use of purified preparations, the map positions of five cell enzymes or their subunits were determined: pyruvate kinase, catalase, glucose-6-phosphate dehydrogenase, hypoxanthine phosphoribosyltransferase, and carbonic anhydrase. The mapping techniques described complement and extend those traditionally used to find human red cell protein variants.
...
PMID:Red cell proteins. I. Two-dimensional mapping of human erythrocyte lysate proteins. 10 31

Somatic cell hybrids between mouse and human cell lines have been used to identify the specific chromosome that governs the synthesis of type I procollagen. Fourteen hybrid clones and subclones were derived independently from crosses between mouse parents [LM (thymidine kinase-negative) or A9 (hypoxanthine phosphoribosyltransferase-negative)] and human cells (human diploid lung fibroblasts WI-38 or diploid skin fibroblasts GM5, GM17, and GM9). The cultures were labeled with [(3)H]proline in modified Eagle's medium without serum. Radioactive procollagens were purified from the medium by the method of Church et al. [(1974) J. Mol. Biol. 86, 785-799]. DEAE-cellulose chromatography was used to separate collagen and type I and type III procollagen. Human type I procollagen was assayed by double immunodiffusion analysis with type I procollagen antibodies prepared by immunizing rabbits with purified human type I procollagen. These analyses combined with karyology and isozyme analyses of each hybrid line have produced evidence for the assignment of the gene for human type I procollagen to chromosome 17. A human microcell-mouse hybrid cell line containing only human chromosome 17 was positive for human type I procollagen, lending further support to the assignment of the human type I procollagen gene to chromosome 17. Finally, by using a hybrid line containing only the long arm of human chromosome 17 translocated onto a mouse chromosome, the type I procollagen gene can be assigned more specifically to the long arm of chromosome 17.
...
PMID:Genetics of the connective tissue proteins: assignment of the gene for human type I procollagen to chromosome 17 by analysis of cell hybrids and microcell hybrids. 41 88

Experiments are described leading to partial compensation of a deficiency in the enzyme hypoxanthine-guanine phosphoribosyltransferase in mutant cells by supplying the cells with exogenous purified enzymes. DEAE-dextran is an effective helper agent, whereas poly (L-lysine), lysolecithin and amphotericin B seem to inhibit the entry of the enzymes of their activity. Enzyme preparation from Chinese hamster was found to have different effects in different mutant cell lines. In mutant Chinese hamster cells, the electrophoretic activity pattern remains unchanged for the Chinese hamster enzyme, but changes progressively to faster-moving activity peaks for the human enzyme after several hours. The metabolic effect of the incorporated enzyme is in the range between 3 and 4% of the normal cellular enzyme activity which corresponds to a 10--20 fold increase of hypoxanthine-guanine phosphoribosyltransferase activity in the mutant cells.
...
PMID:The incorporation of homologous and heterologous hypoxanthine-guanine phosphoriboxyltransferase into mutant cells. 56 35

Human hypoxanthine/guanine phosphoribosyltransferase (EC 2.4.2.8) was purified from red blood cells by the following two methods. Method A includes (a) elimination of hemoglobin by DEAE-cellulose, (b) DEAE-Sephadex chromatography, (c) specific elution of the enzyme from CM-Sephadex by pyrophosphate and (d) Sephadex G-100 gel filtration. Method B includes (a) elimination of hemoglobin by DEAE-cellulose, (b) acid treatment at pH 4.5, (c) ammonium sulfate fractionation, (d) DEAE-Sephadex chromatography, (e) heat treatment at 85 degrees C and (f) Sephadex G-100 gel filtration. Homogeneous enzyme preparation was obtained by the two methods with 8000-9000-fold purification. The sedimentation coefficient (S20,w) was 5.5--5.6 S, and the molecular weight of the enzyme was estimated at about 85000 by the sedimentation equilibrium method. The subunit molecular weight of the untreated protein and S-carboxymethylmaleyl protein was estimated as 41000--45000 by the sedimentation equilibrium method in the presence of guanidine hydrochloride. However, the subunit size estimated by the sodium dodecylsulfate gel electrophoresis was only 26000. Amino acid composition of the enzyme was determined. Glucosamine, sialic acid and hexose were not detected in the enzyme.
...
PMID:Purification and characterization of human hypoxanthine/guanine phosphoribosyltransferase. 88 Sep 43

Conditions were characterized for maximizing the uptake of exogenous mammalian cell DNA by hypoxanthine-guanine phosphoribosyltransferase-deficient Chinese hamster lung cells. Recipient cell cultures in an exponential growth phase were found to be more competent in taking up DNA than stationary cultures. Polyornithine enhanced the uptake of exogenous DNA more reproducibly and to a greater extent than did any of the other facilitators tested (DEAE-dextran, CaCl2, latex spheres, spermine, polylysine and polyarginine). Maximal DNA incorporation occurred when polyornithine and DNA were mixed together prior to inoculation. About 25-30% of the DNA inoculum became deoxyribonuclease-resistant in a typical experiment utilizing polyornithine as the facilitator. Both homologous and heterologous exogenous DNAs rapidly became associated with recipient cell nuclei: approximately 95% of the deoxyribonuclease-resistant donor DNA was nuclear-associated 15 min after inoculation.
...
PMID:Optimal conditions for uptake of exogenous DNA by Chinese hamster lung cells deficient in hypoxanthine-guanine phosphoribosyltransferase. 116 8

Male New Zealand White rabbits were immunized with human adenine phosphoribosyltransferase (APRT) and hypoxanthine-guanine phosphoribosyltransferase (HGPRT), which were purified about 2000-fold and 800-fold, respectively, from erythrocytes by DEAE-cellulose chromatography, ammonium sulfate precipitation and preparative polyacrylamide gel electrophoresis. Specific immunoprecipitations of APRT and HGPRT were achieved with the antisera that were obtained and by using polyethylene glycol as a substitute for goat anti-(rabbit) gamma globulin. The activities of the human forms of these enzymes, whether from red blood cells or from cultured cells, were almost completely eliminated under the conditions of immunoprecipitation used. Little or no reduction of APRT and HGPRT activities from mouse and Chinese hamster cells was observed. This discriminatory capacity of the antisera was successfully used for the identification of human APRT and HGPRT in human-mouse and human-hamster cell hybrids using the immunoprecipitation reaction.
...
PMID:Adenine phosphoribosyltransferase and hypoxanthine-guanine phosphoribosyltransferase immunoprecipitation reactions in human-mouse and human-hamster cell hybrids. 118 4

The growth inhibitory activity of 3-deazaguanosine toward a mutant line (TGR-3) of Chinese hamster ovary cells deficient in hypoxanthine-guanine phosphoribosyltransferase (EC 2.4.2.8) was substantially reversed by the simultaneous addition of nicotinamide riboside. The activities of most other ribonucleoside analogues tested were unaffected. The formation of cellular 3-deazaGMP and 3-deazaGTP from the ribonucleoside analogue, as measured by high-pressure liquid chromatography, was inhibited by the presence of nicotinamide riboside. The inhibition was dependent on concentration of 3-deazaguanosine and could also be demonstrated by following the metabolism of 3-deazaguanosine, labeled with 14C in the ribose moiety, to [14C]3-deazaGTP. In the presence of 100 microM nicotinamide riboside formation of the labeled triphosphate derivative of 3-deazaguanosine was undetectable. A 3-deazaguanosine phosphorylating activity was separated from other cellular kinases by DEAE-cellulose chromatography. Contaminating purine nucleoside phosphorylase (EC 2.4.2.1) was subsequently removed by sucrose density gradient centrifugation. The resulting enzyme preparation demonstrated the greatest activities with nicotinamide riboside and 3-deazaguanosine and, in addition, could also phosphorylate tiazofurin and guanosine to lesser, but significant, degrees. These and other observations suggest that 3-deazaguanosine, and perhaps other agents such as tiazofurin, may, at least in part, be phosphorylated by a nicotinamide ribonucleoside kinase in these cells. If so, it is possible that the activity of this agent in other types of cells in vivo could be dependent upon the presence of this enzyme and that it could be influenced by cellular concentrations of the natural pyridine nucleoside.
...
PMID:Phosphorylation of 3-deazaguanosine by nicotinamide riboside kinase in Chinese hamster ovary cells. 255 47

The adenine phosphoribosyltransferase (APRTase) and hypoxanthine-guanine phosphoribosyltransferase (HGPRTase) activities from promastigotes of Leishmania donovani have been purified to homogeneity using ammonium sulfate precipitation, DEAE-cellulose exclusion, and either AMP-agarose (APRTase) or GTP-agarose (HGPRTase) affinity chromatography. The specific activities of the affinity-purified APRTase and HGPRTase fractions were 326-fold and 1341-fold greater than those in the 40-80% ammonium sulfate precipitate, respectively. The purified APRTase migrated as a single band on sodium dodecyl sulfate (SDS) polyacrylamide gels with a size of 29 kDa, while HGPRTase was also determined to be homogeneous by SDS gel electrophoresis with a size of 24 kDa. In addition, a mutant cell line, APPB2, partially deficient in APRTase activity, still contained quantities of purifiable APRTase protein, while a clonal secondary derivative of the APPB2 cell line that is completely deficient in APRTase activity, APPB2-640A3, failed to express purifiable APRTase protein. The homogeneous enzymes possessed apparent Km values for their nucleobase substrates between 2.0 and 5.0 microM, and both enzymes were inhibited by their immediate or ultimate reaction endproducts, APRTase by AMP and PPi and HGPRTase by GMP, GTP, and PPi. The generation of homogeneous preparations of APRTase and HGPRTase protein will serve as a prerequisite for the generation of immunological and molecular biological probes to analyze the leishmanial phosphoribosyltransferases.
...
PMID:Purification and characterization of the adenine phosphoribosyltransferase and hypoxanthine-guanine phosphoribosyltransferase activities from Leishmania donovani. 270 89

Mutant sublines were derived of S49 mouse T-lymphoma cells that were resistant to tritiated deoxyadenosine. Twenty-five isolates that were selected in 1 microCi/ml of the nucleoside were cross-resistant to 6-thioguanine, were sensitive to HAT (hypoxanthine, aminopterin, and thymidine), and contained less than 1% of hypoxanthine phosphoribosyltransferase activity in wild-type cells. One of the mutant clones, S49-dA2, was further subjected to selection in a medium containing 2 microCi/ml tritiated deoxyadenosine and 1 microgram/ml deoxycoformycin, an inhibitor of adenosine deaminase. All resistant subclones were cross-resistant to tubercidin, 6-methylmercaptopurine riboside, and arabinosyladenine. One of the subclones, S49-12, was completely devoid of adenosine kinase and was partially deficient in deoxyadenosine kinase. This subclone, however, contained wild-type levels of deoxycytidine kinase. DEAE chromatography of the wild-type cell extracts revealed two deoxyadenosine phosphorylating activities, one of which coeluted with adenosine kinase and was the enzyme missing in S49-12. The other species phosphorylated both deoxyadenosine and deoxycytidine, of which deoxycytidine was the preferred substrate.
...
PMID:Adenosine kinase deficiency in tritiated deoxyadenosine-resistant mouse S49 lymphoma cell lines. 283 56

Transfer of genetic information from isolated mammalian chromosomes to recipient cells has been demonstrated. Metaphase chromosomes isolated from Chinese hamster fibroblasts were incubated with mouse A(9) cells containing a mutation at the hypoxanthine-guanine phosphoribosyl transferase (hprt) locus. Cells were plated in a selective medium, resulting in death of all unaltered parental A(9) cells. However, colonies of cells containing hypoxanthine phosphoribosyl transferase (EC 2.4.2.8) appeared with a variable frequency of about 10(-6) to 10(-7). The enzyme from these cells was indistinguishable from that from Chinese hamster cells, as shown by DEAE-cellulose chromatography and gel electrophoresis, and differed clearly from the mouse enzyme. The colonies, thus, did not result from reversion of A(9) parental cells to wild type, but appeared to represent progeny of individual cells that had ingested chromosomes, replicated, and expressed the hprt gene. These colonies differed from each other in stability of expression of the transferred gene.
...
PMID:Transfer of genetic information by purified metaphase chromosomes. 451 24


1 2 Next >>

---