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Joshi nee Pant G, Singh P, Rawat BS, Rawat MSM, Joshi GC. Synthesis, characterization and fluorescence studies of 3,5-diaryl substituted 2-pyrazolines. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2011; 78:1075-9. [PMID: 21233011 DOI: 10.1016/j.saa.2010.12.053] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2010] [Revised: 11/24/2010] [Accepted: 12/14/2010] [Indexed: 05/22/2023]
Abstract
A series of 2-pyrazolines have been synthesized from α, β unsaturated ketones and hydrazine hydrate with acetic/formic acid in ethanol/DMSO. The structures of 2-pyrazolines have been established by spectroscopic techniques i.e. UV, IR, (1)H NMR, (13)C NMR and micro element analysis. Fluorescence spectra were recorded in the solution at fixed concentration and same excitation wavelength at 290 nm. The absorption band positions of all the compounds broadly lie between 280 and 336 nm and fluorescence band positions in the range between 300 and 370 nm, the near ultraviolet region.
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Affiliation(s)
- Geeta Joshi nee Pant
- Department of Chemistry, HNB Garhwal University, Srinagar (Garhwal), Uttarakhand, India.
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52
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Mumin AM, Barrett JW, Dekaban GA, Zhang J. Dendritic cell internalization of foam-structured fluorescent mesoporous silica nanoparticles. J Colloid Interface Sci 2011; 353:156-62. [DOI: 10.1016/j.jcis.2010.09.012] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2010] [Revised: 09/02/2010] [Accepted: 09/03/2010] [Indexed: 12/23/2022]
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53
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Wu H, Lin L, Wang P, Jiang S, Dai Z, Zou X. Solubilization of pristine fullerene by the unfolding mechanism of bovine serum albumin for cytotoxic application. Chem Commun (Camb) 2011; 47:10659-61. [DOI: 10.1039/c1cc13953c] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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54
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Burattini S, Greenland BW, Merino DH, Weng W, Seppala J, Colquhoun HM, Hayes W, Mackay ME, Hamley IW, Rowan SJ. A Healable Supramolecular Polymer Blend Based on Aromatic π−π Stacking and Hydrogen-Bonding Interactions. J Am Chem Soc 2010; 132:12051-8. [DOI: 10.1021/ja104446r] [Citation(s) in RCA: 682] [Impact Index Per Article: 48.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Stefano Burattini
- Department of Chemistry, University of Reading, Whiteknights, Reading RG6 6AD, U.K., Department of Materials Science and Engineering, University of Delaware, Newark, Delaware 19716, and Department of Macromolecular Science and Engineering, Case Western Reserve University, 2100 Adelbert Road, Cleveland, Ohio 44106
| | - Barnaby W. Greenland
- Department of Chemistry, University of Reading, Whiteknights, Reading RG6 6AD, U.K., Department of Materials Science and Engineering, University of Delaware, Newark, Delaware 19716, and Department of Macromolecular Science and Engineering, Case Western Reserve University, 2100 Adelbert Road, Cleveland, Ohio 44106
| | - Daniel Hermida Merino
- Department of Chemistry, University of Reading, Whiteknights, Reading RG6 6AD, U.K., Department of Materials Science and Engineering, University of Delaware, Newark, Delaware 19716, and Department of Macromolecular Science and Engineering, Case Western Reserve University, 2100 Adelbert Road, Cleveland, Ohio 44106
| | - Wengui Weng
- Department of Chemistry, University of Reading, Whiteknights, Reading RG6 6AD, U.K., Department of Materials Science and Engineering, University of Delaware, Newark, Delaware 19716, and Department of Macromolecular Science and Engineering, Case Western Reserve University, 2100 Adelbert Road, Cleveland, Ohio 44106
| | - Jonathan Seppala
- Department of Chemistry, University of Reading, Whiteknights, Reading RG6 6AD, U.K., Department of Materials Science and Engineering, University of Delaware, Newark, Delaware 19716, and Department of Macromolecular Science and Engineering, Case Western Reserve University, 2100 Adelbert Road, Cleveland, Ohio 44106
| | - Howard M. Colquhoun
- Department of Chemistry, University of Reading, Whiteknights, Reading RG6 6AD, U.K., Department of Materials Science and Engineering, University of Delaware, Newark, Delaware 19716, and Department of Macromolecular Science and Engineering, Case Western Reserve University, 2100 Adelbert Road, Cleveland, Ohio 44106
| | - Wayne Hayes
- Department of Chemistry, University of Reading, Whiteknights, Reading RG6 6AD, U.K., Department of Materials Science and Engineering, University of Delaware, Newark, Delaware 19716, and Department of Macromolecular Science and Engineering, Case Western Reserve University, 2100 Adelbert Road, Cleveland, Ohio 44106
| | - Michael E. Mackay
- Department of Chemistry, University of Reading, Whiteknights, Reading RG6 6AD, U.K., Department of Materials Science and Engineering, University of Delaware, Newark, Delaware 19716, and Department of Macromolecular Science and Engineering, Case Western Reserve University, 2100 Adelbert Road, Cleveland, Ohio 44106
| | - Ian W. Hamley
- Department of Chemistry, University of Reading, Whiteknights, Reading RG6 6AD, U.K., Department of Materials Science and Engineering, University of Delaware, Newark, Delaware 19716, and Department of Macromolecular Science and Engineering, Case Western Reserve University, 2100 Adelbert Road, Cleveland, Ohio 44106
| | - Stuart J. Rowan
- Department of Chemistry, University of Reading, Whiteknights, Reading RG6 6AD, U.K., Department of Materials Science and Engineering, University of Delaware, Newark, Delaware 19716, and Department of Macromolecular Science and Engineering, Case Western Reserve University, 2100 Adelbert Road, Cleveland, Ohio 44106
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Milch G, Szabó E. Derivative spectrophotometric assay of acetaminophen and spectrofluorimetric determination of its main impurity. J Pharm Biomed Anal 1991; 9:1107-13. [PMID: 1822180 DOI: 10.1016/0731-7085(91)80051-a] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Second derivative UV spectrophotometry proved to be a useful tool for the determination of acetaminophen, even in the presence of high amounts of the impurity, 4-aminophenol and the background effect caused by dissolved excipients of some dosage forms. The fluorimetric method used for the estimation of 4-aminophenol impurity is less sensitive than the colorimetric methods used in the pharmacopeias. This can be attributed to an inner-filter effect.
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Affiliation(s)
- G Milch
- CHINOIN Pharmaceutical and Chemical Works Ltd, Quality Control Department, Budapest, Hungary
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57
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Substituent effects on the photoisomerization of 5(E)-styryl-1,3-dimethyluracil. J Photochem Photobiol A Chem 1989. [DOI: 10.1016/1010-6030(89)80019-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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58
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Smitka CM, Jackson SG. Rapid fluorogenic assay for differentiation of the Candida parapsilosis group from other Candida spp. J Clin Microbiol 1989; 27:203-6. [PMID: 2492299 PMCID: PMC267266 DOI: 10.1128/jcm.27.1.203-206.1989] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
A 30-min fluorogenic test was developed for differentiation of members of the Candida parapsilosis group from other Candida species commonly encountered in clinical material. The fluorogenic substrate, 4-methylumbelliferyl-beta-D-glucoside, was utilized to assay beta-glucosidase activity. A total of 50 C. parapsilosis isolates and 135 isolates of four other Candida species were tested. Assay sensitivity and specificity were 100 and 99.3%, respectively. The procedure was adapted for use with a spectrofluorometer.
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Affiliation(s)
- C M Smitka
- Laboratory Services Branch, Ontario Ministry of Health, Toronto, Canada
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59
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Methods for determination of vitamin B6foods and other biological materials: A critical review. J Food Compost Anal 1988. [DOI: 10.1016/0889-1575(88)90014-2] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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60
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Davidson AG, Hassan SM. The simultaneous assay of emetine and cephaeline in ipecacuanha and its preparations by spectrofluorimetry. J Pharm Biomed Anal 1984; 2:441-8. [PMID: 16867724 DOI: 10.1016/0731-7085(84)80047-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/1983] [Revised: 01/04/1984] [Indexed: 11/26/2022]
Abstract
A rapid assay is described for the simultaneous determination of emetine and cephaeline in ipecacuanha and its preparations, based upon the different fluorescence intensities of the alkaloids at pH 1 and pH 12. The assay involves the measurement of fluorescence at 317 nm of dilutions of the sample in 0.1 M hydrochloric acid (pH 1) and 0.01 M sodium hydroxide (pH 12) with an excitation wavelength of 283 nm. Concentrations of the individual alkaloids are calculated using two simultaneous equations derived from the experimentally determined coefficients of fluorescence of solutions (1 mug/ml) of emetine and cephaeline at pH 1 and pH 12. The procedure, which has been shown to be accurate, precise and sensitive, requires only 1 ml of a liquid sample and less than 0.5 g of powdered root. There was reasonable agreement between the total concentrations of alkaloids in tinctures and liquid extracts of ipecacuanha determined by the spectrofluorimetric method and by the titrimetric procedure of the British Pharmacopoeia. The fluorimetric procedure gave higher levels of alkaloids in the powdered root than did the B.P. method; this difference is explained by incomplete extraction of the alkaloids in the B.P. procedure for powdered ipecacuanha root.
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Affiliation(s)
- A G Davidson
- Department of Pharmacy, University of Strathclyde, George Street, Glasgow G1 1XW, UK
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62
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Abstract
Fluorescein's property of fluorescence is reviewed. Of the many factors which affect its fluorescence, concentration is probably the most important and it best explains why leaking aqueous turns fluorescein bright green during Seidel's test. The intensity and pattern of fluorescein staining of corneal lesions is probably due to the concentration and distribution of fluorescein in the cornea. The concentration of fluorescein achieved in the retinal blood vessels during fluorescein angiography affects its fluorescence.
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63
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64
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Sundt TM, Anderson RE, Van Dyke RA. Brain pH measurements using a diffusible, lipid soluble pH sensitive fluorescent indicator. J Neurochem 1978; 31:627-35. [PMID: 28382 DOI: 10.1111/j.1471-4159.1978.tb07834.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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65
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Sundt TM, Anderson RE, Sharbrough FW. Effect of hypocapnia, hypercapnia, and blood pressure on NADH fluorescence, electrical activity, and blood flow in normal and partially ischemic monkey cortex. J Neurochem 1976; 27:1125-33. [PMID: 12170599 DOI: 10.1111/j.1471-4159.1976.tb00319.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Nicotinamide adenine dinucleotide fluorescence, cortical reflectance, cortical blood flow, and electroencephalograms were recorded from squirrel monkey brains before, during, and after focal transient cerebral ischemia produced by the temporary clipping of the middle cerebral artery. After release of the occluding clip, the monkeys were followed through an N2-breathing cycle and then to death from anoxia. The effects of controlled variations in arterial carbon dioxide tensions (PaCO2) and mean arterial blood pressures (MABP) were investigated in normal and in ischemic brain. In normal brain, with preserved autoregulation, NADH fluorescence was constant through a wide range in Paco2, MABP, and cortical blood flow. In ischemic brain, NADH levels increased, correlated closely with decreased cortical blood flow and EEG abnormalities, and became dependent on MABP. Artifacts in fluorescent measurements were reduced by: monochromators for excitation, emission, and reflected light; low intensity vertical excitation energy and high sensitivity recording instrumentation; and a small avascular (123 microns) field.
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Affiliation(s)
- T M Sundt
- Cerebrovascular Clinical Research Center, Mayo Clinic, Mayo Foundation, Rochester, MN 55901, USA
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66
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Bubis JJ, Wolman M. Oxidation of lipids and membranes II: Effects of oxidants on cerebral white matter homogenates. JOURNAL OF SUPRAMOLECULAR STRUCTURE 1975; 3:90-101. [PMID: 1152470 DOI: 10.1002/jss.400030110] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Bovine cerebral white matter homogenates were oxidized by various oxidizing solutions of equal molarity and subsequently extracted with water. Most of the oxidants tested (K-dichromate, FeCL3, H2O2, O2, and chloroperbenzoic, ascorbic, performic, and periodic acids) rendered the various myelin constituents less extractable than the constituents of unoxidized control homogenates. KMnO4, and to a lesser degree hemoglobin, rendered myelin constituents more extractable with water than those of the control homogenates. The findings indicate that most of the oxidants produced stabilization of the lamellar pattern, probably through cross-linking and polymerization. KMnO4 and hemoglobin caused labilization and breakdown of the membranous structure. Proof that stabilization of membranes is caused by some oxidants and that fragmentation occurs by the action of KMnO4 and hemoglobin was obtained by the light scattering technique and by electron microscopy of the oxidized homogenates. Evidence obtained indicated that formation of hydrophobic end groups during oxidation favors polymerization, while prevalence of hydrophilic groups is associated with fragmentation.
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67
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68
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69
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Wood PR. Letter: The fluorescence of paracetamol--a re-examination. J Pharm Pharmacol 1973; 25:765-6. [PMID: 4148521 DOI: 10.1111/j.2042-7158.1973.tb10068.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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70
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Martin AR. Spectroscopic methods in biology, with application to neurophysiology. ADVANCES IN BIOLOGICAL AND MEDICAL PHYSICS 1973; 14:225-84. [PMID: 4353469 DOI: 10.1016/b978-0-12-005214-1.50009-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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71
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Rho JH. The organic analysis and carbon chemistry of lunar samples: their significance for exobiology. Fluorescence spectroscopy. SPACE LIFE SCIENCES 1972; 3:360-73. [PMID: 4650295 DOI: 10.1007/bf00926765] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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72
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Abstract
Media and an analytical scheme have been developed which allow both a qualitative and quantitative estimation of the formation of pyocyanine, related phenazines, pyorubrin, and a blue and a yellow-green fluorescent pigment by Pseudomonas aeruginosa. Use of the defined pyocyanine medium of Frank and DeMoss with sulfate or various organic sulfur sources allowed formation of pyocyanine, related phenazines, and pyorubrin. When sulfite was the sulfur source with or without iron, P. aeruginosa formed either a yellow-green or a blue fluorescent pigment. Formation of fluorescent pigments of P. aeruginosa is related to the ability of sulfite to act as a specific sulfur source. In an investigation of the role of both added iron and sulfur sources, complex patterns of pigment formation were observed. In addition to the fluorescent pigments, sulfite also supported the formation of slime by P. aeruginosa.
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73
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Frei RW, Belliveau PE. pH-Sensitive fluorogenic spray reagents. Chromatographia 1972. [DOI: 10.1007/bf02270891] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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74
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Rushton ML, Sammons HG, Robinson BH. A study of calcium absorption using an automated fluorimetric assay procedure. Clin Chim Acta 1971; 35:5-16. [PMID: 5127006 DOI: 10.1016/0009-8981(71)90286-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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75
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76
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Thompson JH, Spezia CA, Angulo M. Fluorometric detection of serotonin and serotonin-O.P.T. Ir J Med Sci 1970; 3:197-220. [PMID: 5427000 DOI: 10.1007/bf02957056] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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77
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78
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Abstract
A precise and reproducible method is described for the ultramicro fluorimetric determination of calcium in plasma, based upon the formation of a fluorescent complex between calcium and calcein at a strongly alkaline pH. In a group of normal subjects, the mean concentration of plasma calcium was 9.66 mg/100 ml with a normal range of 8.9 to 10.4 mg/100 ml.
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79
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Anthony C, Zatman LJ. The microbial oxidation of methanol. The prosthetic group of the alcohol dehydrogenase of Pseudomonas sp. M27: a new oxidoreductase prosthetic group. Biochem J 1967; 104:960-9. [PMID: 6049934 PMCID: PMC1271238 DOI: 10.1042/bj1040960] [Citation(s) in RCA: 144] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
1. The purified alcohol dehydrogenase of Pseudomonas sp. M27, whose action is independent of nicotinamide nucleotides, has absorption peaks at 280mmu and at 350mmu with little or no absorption at or above 450mmu. 2. It does not fluoresce, but green-fluorescent material, diffusible on dialysis, is produced when the enzyme is treated with acid or alkali or when it is boiled. 3. Evidence is presented that the enzyme is not a flavoprotein. 4. Kinetic studies show a correlation between enzyme inactivation by acid, alkali or heat and liberation of the fluorescent material. 5. Some purification of the fluorescent material was achieved, but definite identification was not possible; the major component has a fluorescence maximum at about 460mmu with excitation maxima at about 260mmu and 365mmu. 6. Data are given (including absorption and fluorescence spectra) that support the suggestion that the prosthetic group of the enzyme is a pteridine derivative. 7. Possible mechanisms of action of the enzyme are discussed.
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80
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Bowman MC, Beroza M. Spectra and analyses of insecticide synergists and related compounds containing the methylenedioxyphenyl group by spectrophotofluorometry (SPF) and spectrophotophosphorimetry (SPP). RESIDUE REVIEWS 1967; 17:1-22. [PMID: 4897158 DOI: 10.1007/978-1-4615-8419-3_1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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81
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Lorenzen CJ. A method for the continuous measurement of in vivo chlorophyll concentration. ACTA ACUST UNITED AC 1966. [DOI: 10.1016/0011-7471(66)91102-8] [Citation(s) in RCA: 96] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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82
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Bridges JW, Davies DS, Williams RT. Fluorescence studies on some hydroxypyridines including compounds of the vitamin B6 group. Biochem J 1966; 98:451-68. [PMID: 5941339 PMCID: PMC1264864 DOI: 10.1042/bj0980451] [Citation(s) in RCA: 79] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
1. The variations with pH (from 36n-sulphuric acid to 10n-sodium hydroxide) of the excitation and fluorescence wavelengths and fluorescence intensity of 2-, 3- and 4-hydroxypyridine and their O- and N-methyl derivatives were investigated. 2. 4-Hydroxy- and 4-methoxy-pyridine were non-fluorescent at all pH values. 3. The cations and dipolar ions of the 3-hydroxypyridine derivatives and the anion of 3-hydroxypyridine were fluorescent, but the neutral forms were not. 4. All the forms of the 2-hydroxypyridine derivatives were fluorescent. 5. Pyridoxol, pyridoxal and its 5-phosphate, pyridoxamine and pyridoxic acid and its lactone were studied similarly. All these compounds, except pyridoxal 5-phosphate, were more fluorescent than 3-hydroxypyridine. 6. The most fluorescent forms of these compounds are the anions, except for pyridoxol, where the dipolar ion was the most fluorescent form. The least fluorescent forms are the neutral molecules. The dipolar ions were appreciably fluorescent in all cases. 7. The most fluorescent form examined was the dianion of pyridoxic acid lactone. 8. The cations were all fluorescent except the cations of 2- and 3-methoxypyridine. All the cations showed excited-state ionization. The excited pK(a) values of these cations were determined and the results are discussed with reference to Weller's (1952) equation relating ground- and excited-state dissociation constants. 9. The pK(a) values for all ionizations undergone by the compounds examined were determined from fluorescence data. 10. Stokes shifts for the various ionic and neutral species of the compounds examined were calculated and are discussed.
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83
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Abstract
1. The variation with pH of the excitation and fluorescence wavelengths and fluorescence intensity of several hydroxy- and amino-biphenyls has been investigated with a view to using the data for the determination of hydroxybiphenyls in biological material. 2. 2- and 3-Hydroxy-, 2,2'-dihydroxy-, and 2-, 3- and 4-amino-biphenyl exhibited excited-state ionization. 4-Hydroxy- and 4,4'-dihydroxybiphenyl did not, and showed normal fluorescence changes with pH. 3. Biphenyl and 2- and 4-methoxybiphenyl showed no changes in fluorescence in the range pH0-14. 4. 4,4'-Dihydroxybiphenyl showed fluorescent peaks corresponding to the un-ionized form, the monoanion and dianion at the appropriate pH values, but 2,2'-dihydroxybiphenyl showed fluorescent peaks corresponding to the un-ionized form and the monoanion only, suggesting that it did not form a dianion. 5. 3- and 4-Nitrobiphenyl were non-fluorescent. 6. These results are discussed.
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84
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Creaven PJ, Parke DV, Williams RT. A spectrofluorimetric study of the 7-hydroxylation of coumarin by liver microsomes. Biochem J 1965; 96:390-8. [PMID: 4378707 PMCID: PMC1207052 DOI: 10.1042/bj0960390] [Citation(s) in RCA: 89] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
1. The fluorescence characteristics of 3- and 7-hydroxycoumarin, and 7-hydroxy-and 7-methoxy-4-methylcoumarin, have been determined. 7-Hydroxycoumarin shows excited-state ionization from pH1 to 9. 2. A sensitive and specific fluorimetric method for the determination of 7-hydroxycoumarin (umbelliferone), and its application to liver homogenates and other tissue preparations, are described. 3. The enzymic hydroxylation of coumarin to 7-hydroxycoumarin has been studied by this method and the optimum conditions have been determined for rabbit-liver preparations. The enzymic activity was found in the microsomal fraction and required NADPH(2) and oxygen. Activity with NADH(2) was one-third of that with NADPH(2). 4. Addition of NADP was necessary for full activity of 10000g supernatant preparations of liver. Nicotinamide added during preparation preserved coenzymic activity in tissue stored at -12 degrees . Glucose 6-phosphate had no effect on the activity of stored or fresh tissue. 5. Inhibition occurred with p-chloromercuribenzoate, and with the usual inhibitors of the microsomal drug-metabolizing enzymes, SKF acid, SKF 525A, and Lilly 7132, but not with 2,2'-bipyridyl. 6. Liver homogenates from rabbit, guinea pig, coypu, cat and pigeon showed activity, but preparations of rat or mouse liver, and of locust fat bodies, did not hydroxylate coumarin to umbelliferone. The enzyme system was absent from rat-liver homogenates and microsomal preparations. Moreover, rat liver also contained inhibitors of the rabbit-liver coumarin-7-hydroxylase system and of the further metabolism of umbelliferone by guinea-pig liver. Guinea-pig-liver preparations hydroxylated coumarin to umbelliferone and then converted this product into its glucuronide. 7. The coumarin-7-hydroxylase activity of female rabbit liver was two to three times that of male rabbit liver.
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