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Directional conformer exchange in dihydrofolate reductase revealed by single-molecule nanopore recordings. Nat Chem 2020; 12:481-488. [DOI: 10.1038/s41557-020-0437-0] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Accepted: 02/10/2020] [Indexed: 12/18/2022]
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2
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Atkinson A, Bradford PA, Selmes IP. The large scale preparation of chromatographic grade hydroxylapatite and its application in protein separation procedures. ACTA ACUST UNITED AC 2007. [DOI: 10.1002/jctb.5020230708] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Wilchek M, Hexter CS. The purification of biologically active compounds by affinity chromatography. METHODS OF BIOCHEMICAL ANALYSIS 2006; 23:347-85. [PMID: 187896 DOI: 10.1002/9780470110430.ch5] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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4
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5
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Thymidylate synthetase overproduction in 5-fluorodeoxyuridine-resistant mouse fibroblasts. Mol Cell Biol 1983. [PMID: 6217415 DOI: 10.1128/mcb.2.9.1118] [Citation(s) in RCA: 37] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We describe the isolation and characterization of a series of 5-fluorodeoxyuridine (FdUrd)-resistant mouse 3T6 cell lines that overproduce thymidylate synthetase (TS) by up to 50-fold compared with the parental cells. The resistant cells were selected by growing 3T6 cells or a methotrexate-resistant 3T6 cell line (M50L3, isolated previously in our laboratory) in gradually increasing concentrations of FdUrd. Uridine and cytidine were included in the culture medium to reduce toxicity from metabolic products of FdUrd. Cells that were resistant to the drug by virtue of loss of thymidine kinase activity were eliminated by selection in medium containing hypoxanthine, methotrexate, and thymidine. M50L3 cells were found to adapt to FdUrd more readily than 3T6 cells. A number of clones were isolated that were able to grow in the presence of 3 microM (M50L3 derived) or 0.3 microM (3T6 derived) FdUrd. Several were found to overproduce TS by 10 to 50-fold compared with normal 3T6 cells. All were found to have thymidine kinase activity, although the enzyme level was significantly reduced in some clones. The overproduced TS was inactivated by 5-fluorodeoxyuridylic acid at the same concentration as the enzyme from 3T6 cells. TS was purified from the LU3-7 clone (50-fold overproducer) by affinity chromatography on methotrexate-polyacrylamide. The monomer molecular weight was about 38,000, which was the same as the molecular weight of the monomer in 3T6 cells. The overproduction trait was gradually lost (half-life, 3 weeks) when LU3-7 cells were grown in the absence of FdUrd. The overproducing cells will provide an abundant supply of TS and (very likely) its mRNA and may serve as a convenient model system for detailed studies of the regulation of TS gene expression during the cell cycle.
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Rossana C, Gollakota Rao L, Johnson LF. Thymidylate synthetase overproduction in 5-fluorodeoxyuridine-resistant mouse fibroblasts. Mol Cell Biol 1982; 2:1118-25. [PMID: 6217415 PMCID: PMC369905 DOI: 10.1128/mcb.2.9.1118-1125.1982] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
We describe the isolation and characterization of a series of 5-fluorodeoxyuridine (FdUrd)-resistant mouse 3T6 cell lines that overproduce thymidylate synthetase (TS) by up to 50-fold compared with the parental cells. The resistant cells were selected by growing 3T6 cells or a methotrexate-resistant 3T6 cell line (M50L3, isolated previously in our laboratory) in gradually increasing concentrations of FdUrd. Uridine and cytidine were included in the culture medium to reduce toxicity from metabolic products of FdUrd. Cells that were resistant to the drug by virtue of loss of thymidine kinase activity were eliminated by selection in medium containing hypoxanthine, methotrexate, and thymidine. M50L3 cells were found to adapt to FdUrd more readily than 3T6 cells. A number of clones were isolated that were able to grow in the presence of 3 microM (M50L3 derived) or 0.3 microM (3T6 derived) FdUrd. Several were found to overproduce TS by 10 to 50-fold compared with normal 3T6 cells. All were found to have thymidine kinase activity, although the enzyme level was significantly reduced in some clones. The overproduced TS was inactivated by 5-fluorodeoxyuridylic acid at the same concentration as the enzyme from 3T6 cells. TS was purified from the LU3-7 clone (50-fold overproducer) by affinity chromatography on methotrexate-polyacrylamide. The monomer molecular weight was about 38,000, which was the same as the molecular weight of the monomer in 3T6 cells. The overproduction trait was gradually lost (half-life, 3 weeks) when LU3-7 cells were grown in the absence of FdUrd. The overproducing cells will provide an abundant supply of TS and (very likely) its mRNA and may serve as a convenient model system for detailed studies of the regulation of TS gene expression during the cell cycle.
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Guynn RW, Labaume LB, Henkin J. Equilibrium constants under physiological conditions for the condensation of acetaldehyde with tetrahydrofolic acid. Arch Biochem Biophys 1982; 217:181-90. [PMID: 7125664 DOI: 10.1016/0003-9861(82)90492-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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8
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Properties of an altered dihydrofolate reductase encoded by amplified genes in cultured mouse fibroblasts. J Biol Chem 1981. [DOI: 10.1016/s0021-9258(19)68791-0] [Citation(s) in RCA: 140] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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Henderson GB, Russell A, Whiteley JM. A fluorescent derivative of methotrexate as an intracellular marker for dihydrofolate reductase in L1210 cells. Arch Biochem Biophys 1980; 202:29-34. [PMID: 6772112 DOI: 10.1016/0003-9861(80)90402-6] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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10
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Dietrich SW, Smith RN, Brendler S, Hansch C. The use of triazine inhibitors in mapping the active site region of Lactobacillus casei dihydrofolate reductase. Arch Biochem Biophys 1979; 194:612-9. [PMID: 109047 DOI: 10.1016/0003-9861(79)90656-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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11
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Cotton RG, Jennings IG. Affinity chromatography of phenylalanine hydroxylase. The structure of a pteridine adsorbent. EUROPEAN JOURNAL OF BIOCHEMISTRY 1978; 85:357-63. [PMID: 648526 DOI: 10.1111/j.1432-1033.1978.tb12247.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
1. Four independent methods have established that the structure of a previously reported pteridine affinity adsorbent, 6,7-dimethyl-5,6,7,8-tetrahydropterin--CH-Sepharose, is 5(CH-Sepharosyl)-6,7-dimethyl-5,6,7,8-tetrahydropterin. 2. A novel reaction, the carbodiimide-promoted coupling of a carboxyl group to N-5 of a tetrahydropterin, is described. 3. Two novel adsorbents, 5-formyl-tetrahydrofolate--AH-Sepharose and 5-methyl-tetrahydrofolate--AH-Sepharose, are described which may be useful not only in the study of phenylalanine hydroxylase but also in the study of folate-metabolizing enzymes.
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Webber S, Deits TL, Snyder WR, Whiteley JM. The purification of rat and sheep liver dihydropteridine reductases by affinity chromatography on methotrexate-sepharose. Anal Biochem 1978; 84:491-503. [PMID: 626393 DOI: 10.1016/0003-2697(78)90068-4] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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13
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McIntyre LJ, Harding NG. Reduction of oxidised folates by dihydrofolate reductase from methotrexate-resistant Lactobacillus casei. BIOCHIMICA ET BIOPHYSICA ACTA 1977; 482:261-71. [PMID: 18181 DOI: 10.1016/0005-2744(77)90240-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The use of alternative substrates by dihydrofolate reductase (5,6,7,8-tetrahydrofolate: NADP+ oxidoreductase, EC 1.5.1.3) was investigated as a possible mechanism for the resistance of Lactobacillus casei to the cytotoxic drug methotrexate. The reduction of folic acid and 10-formylfolic acid by homogeneous enzyme was compared to that of the normal substrate, dihydrofolic acid. The three substrates have different pH optima and Km values. In addition, it was found that the reduction of 10-formylfolic acid was markedly stimulated by the presence of ions. Although the reduction was sensitive to methotrexate in all cases, the ion activation may be of importance in partially inhibited systems.
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Whiteley JM, Henderson GB, Russell A, Singh P, Zevely EM. The isolation of dihydrofolate reductases by affinity chromatography on folate-sepharose. Anal Biochem 1977; 79:42-51. [PMID: 405885 DOI: 10.1016/0003-2697(77)90376-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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15
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Dann JG, Ostler G, Bjur RA, King RW, Scudder P, Turner PC, Roberts GC, Burgen AS. Large-scale purification and characterization of dihydrofolate reductase from a methotrexate-resistant strain of Lactobacillus casei. Biochem J 1976; 157:559-71. [PMID: 10886 PMCID: PMC1163897 DOI: 10.1042/bj1570559] [Citation(s) in RCA: 115] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Dihydrofolate reductase has been purified from a methotrexate-resistant strain of Lactobacillus casei NCB 6375. By careful attention to growth conditions, up to 2.5 g of enzyme is obtained from a 400 litre culture. The purification procedure, involving poly-ethyleneimine treatment, DEAE-cellulose chromatography and affinity chromatography on methotrexate-aminohexyl-Sepharose, operates on the gram scale, with overall yields of 50-60%. Elution of the affinity column by reverse (upward) flow was used, as it led to recovery of the enzyme in a much smaller volume. The enzyme obtained appears to be more than 98% pure, as judged by gel electrophoresis, isoelectric focusing, and gel filtration. It has a mol.wt. of approx. 17900 and a turnover number of 4s-1 (50mM-triethanolamine/400mM-KCl, pH 7.2, 25 degrees C) with dihydrofolate and NADPH as substrates. The turnover number for folate is 0.02s-1. Michaelis constants for a variety of substrates have been measured by using a new fluorimetric assay (0.36 muM-dihydrofolate; 0.78 muM-NADPH), and binding constants determined by using the quenching of protein fluorescence (dihydrofolate, 2.25 X 10(6)M-1; NADPH, greater than 10(8)M-1). The pH/activity profile shows a single maximum at pH 7.3; at this pH, marked activation by 0.5M-NaCl is observed.
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16
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Synthesis and degradation of folate reductase in sensitive and methotrexate-resistant lines of S-180 cells. J Biol Chem 1976. [DOI: 10.1016/s0021-9258(17)33500-7] [Citation(s) in RCA: 117] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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17
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Kamen BA, Caston JD. Purification of folate binding factor in normal umbilical cord serum. Proc Natl Acad Sci U S A 1975; 72:4261-4. [PMID: 676 PMCID: PMC388700 DOI: 10.1073/pnas.72.11.4261] [Citation(s) in RCA: 44] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Human umbilical cord serum was found to contain both free folate and folate complexed to a high-molecular weight factor. The complexed folate was bound to a very high affinity binder and was present in concentrations equivalent to as much as 60 ng of 5-methyltetrahydrofolic acid per ml of serum. Acidification of the serum caused disassociation of the folate-binder complex. Released folates were separated from binder by Sephadex gel filtration, zonal centrifugation through sucrose gradients, or adsorption onto activated charcoal. The separated binding factor, either saturated or unsaturated with folate, had a molecular weight of about 40,000 on Sephadex G-200 chromatography. Binding of [3H]pteroylglutamic acid was rapid and, as in the original endogenous folate-binder complex, was essentially irreversible at neutral pH. The affinity and specificity of the binder were examined by competition experiments using [3H]pteroylglutamic acid and nonradioactive folate derivatives. Oxidized folates were bound in preference to reduced derivatives, but only three to four times more unlabeled 5-methyltetrahydrofolic acid than pteroylglutamic acid was required to produce an equal level of competition. The strong affinity for 5-methyltetrahydrofolic acid, the main serum folate, suggests that the binder could be part of the mechanism by which the fetus concentrates maternally supplied folate for its growth and development.
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Tattersall MH, Brown B, Frei E. The reversal of methotrexate toxicity by thymidine with maintenance of antitumour effects. Nature 1975; 253:198-200. [PMID: 1078601 DOI: 10.1038/253198a0] [Citation(s) in RCA: 59] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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19
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Manteuffel-Cymborowska M, Zielińska ZM. Purification and properties of an insect dihydrofolate reductase. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. B, COMPARATIVE BIOCHEMISTRY 1975; 50:35-40. [PMID: 1122719 DOI: 10.1016/0305-0491(75)90295-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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20
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Tzortzatou F, Hayhoe FG. The effect of folate antagonists on dihydrofolate reductase activity demonstrated cytochemically. Br J Haematol 1974; 28:209-16. [PMID: 4433479 DOI: 10.1111/j.1365-2141.1974.tb06655.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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21
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Isolation and Characterization of the Multiple Forms of Dihydrofolate Reductase from Methotrexate-resistant Hamster Cells. J Biol Chem 1974. [DOI: 10.1016/s0021-9258(19)42894-9] [Citation(s) in RCA: 35] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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22
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Morris HR, Batley KE, Harding NC, Bjur RA, Dann JG, King RW. Dihydrofolate reductase: low-resolution mass-spectrometric analysis of an elastase digest as a sequencing tool. Biochem J 1974; 137:409-11. [PMID: 4207389 PMCID: PMC1166130 DOI: 10.1042/bj1370409] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
An elastase digest of a protein of unknown structure, dihydrofolate reductase, was studied by mass spectrometry. This soluble digest contained a large number of small peptides in different yields, within the ideal molecular-weight range (200-1200) for mixture-analysis mass spectrometry. Sequences of the major component peptides in the digest are reported.
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Craven DB, Harvey MJ, Lowe CR, Dean PD. Affinity chromatography on immobilised adenosine 5'-monophosphate. 1. A new synthesis and some properties of an N6-immobilised 5'-AMP. EUROPEAN JOURNAL OF BIOCHEMISTRY 1974; 41:329-33. [PMID: 4593579 DOI: 10.1111/j.1432-1033.1974.tb03273.x] [Citation(s) in RCA: 59] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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24
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Craven DB, Harvey MJ, Dean PD. The synthesis of N6-(6-aminohexyl)-NAD+ and its application to affinity chromatography. FEBS Lett 1974; 38:320-4. [PMID: 4153149 DOI: 10.1016/0014-5793(74)80082-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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25
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Pastore EJ, Plante LT, Kisliuk RL. Pteroyllysine-agarose in the purification of dihydrofolate reductase. Methods Enzymol 1974; 34:281-8. [PMID: 4217415 DOI: 10.1016/s0076-6879(74)34026-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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26
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Dean PD, Craven DB, Harvey MJ, Lowe CR. An analysis of affinity chromatography using immobilised alkyl nucleotides. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1974; 42:99-121. [PMID: 4152332 DOI: 10.1007/978-1-4684-6982-0_8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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27
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Williams MN, Greenfield NJ, Hoogsteen K. Evidence for Two Reduced Triphosphopyridine Nucleotide Binding Sites on Dihydrofolate Reductase from a Methotrexate-resistant Strain of Escherichia coli. J Biol Chem 1973. [DOI: 10.1016/s0021-9258(19)43457-1] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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28
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Makulu DR, Smith EF, Betino JR. Lack of dihydrofolate reductase activity in brain tissue of mammalian species: possible implications. J Neurochem 1973; 21:241-5. [PMID: 4720900 DOI: 10.1111/j.1471-4159.1973.tb04244.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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29
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Gauldie J, Marshall L, Hillcoat BL. Purification and properties of dihydrofolate reductase from cultured mammalian cells. Biochem J 1973; 133:349-56. [PMID: 4723779 PMCID: PMC1177704 DOI: 10.1042/bj1330349] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Dihydrofolate reductase was purified quickly and simply from small quantities of cultured mammalian cells by affinity chromatography. On gel electrophoresis of the purified enzyme, multiple bands of activity resulted from enzyme-buffer interaction at low but not high buffer concentration. A Ferguson plot (Ferguson, 1964) showed that this heterogeneity was due to a charge difference with no alteration in the size of the enzyme. Stimulation of enzyme activity by KCl, urea and p-hydroxymercuribenzoate, and inhibition by methotrexate and trimethoprim, showed only minor differences between the various enzymes.
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30
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Shaltiel S, Er-El Z. Hydrophobic chromatography: use for purification of glycogen synthetase. Proc Natl Acad Sci U S A 1973; 70:778-81. [PMID: 4197628 PMCID: PMC433357 DOI: 10.1073/pnas.70.3.778] [Citation(s) in RCA: 221] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
A homologous series of omega-aminoalkylagaroses [Sepharose-NH(CH(2))(n)NH(2)] that varied in the length of their hydrocarbon side chains was synthesized. This family of agaroses was used for a new type of chromatography, in which retention of proteins is achieved mainly through lipophilic interactions between the hydrocarbon side chains on the agarose and accessible hydrophobic pockets in the protein. When an extract of rabbit muscle was subjected to chromatography on these modified agaroses, the columns with short "arms" (n = 2 and n = 3) excluded glycogen synthetase (EC 2.4.1.11), but the enzyme was retained on delta-aminobutyl-agarose (n = 4), from which it could be eluted with a linear NaCl gradient. Higher members of this series (e.g., n = 6) bind the synthetase so tightly that it can be eluted only in a denatured form. A column of delta-aminobutyl-agarose, which retained the synthetase, excluded glycogen phosphorylase (EC 2.4.1.1), which in this column series and under the same conditions requires side chains 5-(or 6)-carbon-atoms long for retention. Therefore, it is possible to isolate glycogen synthetase by passage of muscle extract through delta-aminobutyl-agarose, then to extract phosphorylase by subjecting the excluded proteins to chromatography on omega-aminohexyl-agarose (n = 6). On a preparative scale, the synthetase (I form) was purified 25- to 50-fold in one step. This paper describes some basic features and potential uses of hydrophobic chromatography. The relevance of the results presented here to the design and use of affinity chromatography columns is discussed.
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31
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Schulz R. Inhibition of rat folic acid reductase activity activity by trimethoprim during the later stages of gestation. NAUNYN-SCHMIEDEBERG'S ARCHIVES OF PHARMACOLOGY 1973; 278:227-30. [PMID: 4268642 DOI: 10.1007/bf00500653] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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32
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Otting F, Huennekens FM. TPNH-dependent binding of amethopterin by dihydrofolate reductase from Lactobacillus casei. Arch Biochem Biophys 1972; 152:429-31. [PMID: 4403695 DOI: 10.1016/0003-9861(72)90234-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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34
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Whiteley JM, Jackson RC, Mell GP, Drais JH, Huennekens FM. Folate antagonists covalently linked to carbohydrates: synthesis, properties, and use in the purification of dihydrofolate reductases. Arch Biochem Biophys 1972; 150:15-22. [PMID: 4623864 DOI: 10.1016/0003-9861(72)90004-5] [Citation(s) in RCA: 34] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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35
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Hiebert M, Gauldie J, Hillcoat BL. Multiple enzyme forms from protein-bromphenol blue interaction during gel electrophoresis. Anal Biochem 1972; 46:433-7. [PMID: 4112507 DOI: 10.1016/0003-2697(72)90316-8] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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36
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Dann JG, Harding NG, Newbold PC, Whiteley JM. Single-step purification of dihydrofolate reductases on pteridine matrices. Biochem J 1972; 127:28P-29P. [PMID: 4403950 PMCID: PMC1178649 DOI: 10.1042/bj1270028p] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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37
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Salter DN, Ford JE, Scott KJ, Andrews P. Isolation of the folate-binding protein from cow's milk by the use of affinity chromatography. FEBS Lett 1972; 20:302-306. [PMID: 11946443 DOI: 10.1016/0014-5793(72)80092-9] [Citation(s) in RCA: 56] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- D N. Salter
- National Institute for Research in Dairying, Shinfield, RG2 9AT, Reading, England
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Smith JL, Barker CR. Antigen release from insoluble polymer complexes by lymphocyte cell suspensions. Clin Exp Immunol 1971; 9:869-77. [PMID: 5168276 PMCID: PMC1713121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Slow release of antigenically active PPD occurs from polyaminostyrene-PPD covalent complexes even after exhaustive washing. Lymphocyte cell suspensions caused an accelerated rate of release which correlated with the tuberculin sensitivity of the donor and the ability of the cells to respond to soluble PPD in vitro by increased DNA synthesis. The release of antigenically active material from these complexes makes them unsuitable as insoluble antigens.
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Cell-free synthesis of tryptophanase from Escherichia coli. Use of ribonucleic acid isolated from induced cells and a comparison of the product from a system employing ribosomes with that from one employing ribosomes and exogenous ribonucleic acid. Biochem J 1971; 125:643-53. [PMID: 4947396 PMCID: PMC1178102 DOI: 10.1042/bj1250643] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
1. Polyribosomes and RNA were isolated from cultures in which tryptophanase (EC 4.2.1.-) was induced. The polyribosomes were incubated under conditions of protein synthesis, in the presence of a radioactive amino acid and a post-ribosomal supernatant fraction obtained from repressed cells. The RNA preparations were incubated under conditions of protein synthesis in the presence of a radioactive amino acid and a supernatant fraction containing ribosomes from repressed cells. 2. The system was characterized and the synthesis of a radioactive protein with the same chromatographic properties as tryptophanase was demonstrated. This synthesis was shown to be time-dependent and required the presence of RNA from induced cultures, ribosomes and an energy supply; it was inhibited by chloramphenicol. 3. The maximum activity for the synthesis of this protein was found to be associated with 23S rRNA isolated from sucrose gradients. 4. The N-terminal amino acid of tryptophanase was labelled in the protein synthesized in this system but not in the protein synthesized by polyribosomes (without added RNA). Conversely, the C-terminal amino acid of tryptophanase was labelled in the polyribosome system but not in the RNA-containing system. 5. Tryptic digests of protein labelled in vitro were compared with those of tryptophanase. No labelled tryptic peptides were identified other than tryptophanase tryptic peptides. An analysis of the results implied that in the polyribosome system almost the complete tryptophanase subunit chain was labelled but that in the RNA-containing system these chains were incompletely synthesized. 6. Sucrose-gradient analysis of protein synthesized in the RNA-containing system suggested that it cannot be converted into structures with the same sedimentation properties as native tryptophanase. 7. The significance of these results for the assay of tryptophanase mRNA and for an understanding of the control of the translation of this mRNA in vivo is discussed.
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