1. Introduction: why biologists need chemistry 2. Atoms: the foundations of life 3. Compounds and... more 1. Introduction: why biologists need chemistry 2. Atoms: the foundations of life 3. Compounds and chemical Bonding: bringing atoms together 4. Molecular Interactions: holding it all together 5. Organic Compounds 1: the framework of life 6. Organic Compounds 2: adding function to the framework of life 7. Biological Macromolecules: providing life's infrastructure 8. Molecular Shape and Structure 1: from atoms to small molecules 9. Molecular Shape and Structure 2: the shape of large molecules 10. Isomerism: generating chemical variety 11. Chemical analysis 1: how do we know what is there? 12. Chemical analysis 2: how do we know how much is there? 13. Energy: what makes reactions go? 14. Kinetics: what affects the speed of a reaction? 15. Equilibria: how far do reactions go? 16. Acids, bases and the aqueous environment: the medium of life 17. Chemical reactions 1: bringing molecules to life 18. Chemical reactions 2: reaction mechanisms driving the chemistry of life
Journal of The Chemical Society-perkin Transactions 2, 1972
... The losses of methyl radicals from both the molecular and M - 1 ions of diphenylmethane have ... more ... The losses of methyl radicals from both the molecular and M - 1 ions of diphenylmethane have been noted by many Johnstone and Millard suggested that the loss of methyl from C13Hll+ came from the central CH unit together with loss of ortho-hydrogens ... AS Siegel, J . Amer. ...
Incubation of 2-[9-14C]acetylaminofluorene (2-[9-14C]AAF) in vitro with rat liver microsomes, lea... more Incubation of 2-[9-14C]acetylaminofluorene (2-[9-14C]AAF) in vitro with rat liver microsomes, leads to covalent binding of label to microsomal proteins. The binding is NADPH-dependent, increases linearly with time, and is inhibited by SKF-525A and 7,8-benzoflavone (7,8-BF). Binding is increased more than 8-fold in microsomes from 3-methylcholanthrene(MC)-pretreated rats, but only less than 2-fold in those from phenobarbital(PB)-pretreated rats. In the presence of cytosolic proteins, there is slight enhancement of the labelling of microsomes and some labelling of the cytosolic proteins. Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) and 2-dimensional gel electrophoresis indicate that covalent labelling by 2-AAF derivatives is concentrated in specific proteins. The pattern of labelling varies between microsomes from animals pretreated with PB, MC and 2-AAF. Factors which may contribute to the specificity of labelling are discussed.
The 19F chemical shifts of a series of bridgehead fluorides are reported. It is found that, contr... more The 19F chemical shifts of a series of bridgehead fluorides are reported. It is found that, contrary to earlier conclusions based on a limited number of substrates, the fluorine shifts occur randomly.
Journal of Photochemistry and Photobiology A-chemistry, 2001
Addition of Fe(III) increases the number of strand breaks of plasmid DNA in aqueous solution unde... more Addition of Fe(III) increases the number of strand breaks of plasmid DNA in aqueous solution under gamma-radiolysis at room temperature and at 77 K. Low temperature radiolysis requires ca. 100 times higher radiation dose for the creation of comparable strand breaks due to the suppression of Fenton-type reactions. Room temperature radiolysis produces a relatively large number of multi-single strand breaks (ssb) and, on absorption of 100 Gy, less double-strand breaks (dsb), ca. 4%, while under cryogenic conditions at a dose of 10 kGy, are produced ca. 10% dsb for a similar total number of strand breaks. Fe(III) in its complex with EDTA exhibits small, but distinct damage to DNA even without irradiation, in comparison to the strong effect of Fe(II)/EDTA. Under our experimental conditions hydrogen peroxide does not influence the damage in a noticeable way in the presence of Fe(II) and Fe(III), although UV light exhibits a very strong effect on the addition of both Fe(III) and H2O2. In our system, iron forms complexes with EDTA and also is bound by other components. A molar excess of iron in relation to EDTA has no striking effect. The chelators seem to be responsible for creation of a reactive form of iron, able to produce reactive oxygen species in solutions containing dissolved air.
Journal of Liquid Chromatography & Related Technologies, 2010
ABSTRACT A new reversed-phase high performance liquid chromatographic (RP-HPLC) method is develop... more ABSTRACT A new reversed-phase high performance liquid chromatographic (RP-HPLC) method is developed and validated for the simultaneous determination of barbitone, allobarbitone, phenobarbitone, cyclobarbitone, hexobarbitone, pentobarbitone, secobarbitone and methohexitone compounds in a single analytical run. The method uses a Phenosphere C18 (150 mm × 4.6 mm; 5 μm) column and isocratic elution. The mobile phase consisted of a mixture of methanol-water (50:50, v/v), pumped at a flow rate of 1.0 mL/min. The UV detection is set at 254 nm. The method is validated with respect to accuracy, precision (repeatability and intermediate precision), specificity, linearity, range robustness and stability of analytical solutions. All the parameters examined met the current recommendations for bioanalytical method validation. The method is specific, simple, selective and reliable for routine use in quality control analysis of barbiturates raw materials for final product release.
1. Introduction: why biologists need chemistry 2. Atoms: the foundations of life 3. Compounds and... more 1. Introduction: why biologists need chemistry 2. Atoms: the foundations of life 3. Compounds and chemical Bonding: bringing atoms together 4. Molecular Interactions: holding it all together 5. Organic Compounds 1: the framework of life 6. Organic Compounds 2: adding function to the framework of life 7. Biological Macromolecules: providing life's infrastructure 8. Molecular Shape and Structure 1: from atoms to small molecules 9. Molecular Shape and Structure 2: the shape of large molecules 10. Isomerism: generating chemical variety 11. Chemical analysis 1: how do we know what is there? 12. Chemical analysis 2: how do we know how much is there? 13. Energy: what makes reactions go? 14. Kinetics: what affects the speed of a reaction? 15. Equilibria: how far do reactions go? 16. Acids, bases and the aqueous environment: the medium of life 17. Chemical reactions 1: bringing molecules to life 18. Chemical reactions 2: reaction mechanisms driving the chemistry of life
Journal of The Chemical Society-perkin Transactions 2, 1972
... The losses of methyl radicals from both the molecular and M - 1 ions of diphenylmethane have ... more ... The losses of methyl radicals from both the molecular and M - 1 ions of diphenylmethane have been noted by many Johnstone and Millard suggested that the loss of methyl from C13Hll+ came from the central CH unit together with loss of ortho-hydrogens ... AS Siegel, J . Amer. ...
Incubation of 2-[9-14C]acetylaminofluorene (2-[9-14C]AAF) in vitro with rat liver microsomes, lea... more Incubation of 2-[9-14C]acetylaminofluorene (2-[9-14C]AAF) in vitro with rat liver microsomes, leads to covalent binding of label to microsomal proteins. The binding is NADPH-dependent, increases linearly with time, and is inhibited by SKF-525A and 7,8-benzoflavone (7,8-BF). Binding is increased more than 8-fold in microsomes from 3-methylcholanthrene(MC)-pretreated rats, but only less than 2-fold in those from phenobarbital(PB)-pretreated rats. In the presence of cytosolic proteins, there is slight enhancement of the labelling of microsomes and some labelling of the cytosolic proteins. Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) and 2-dimensional gel electrophoresis indicate that covalent labelling by 2-AAF derivatives is concentrated in specific proteins. The pattern of labelling varies between microsomes from animals pretreated with PB, MC and 2-AAF. Factors which may contribute to the specificity of labelling are discussed.
The 19F chemical shifts of a series of bridgehead fluorides are reported. It is found that, contr... more The 19F chemical shifts of a series of bridgehead fluorides are reported. It is found that, contrary to earlier conclusions based on a limited number of substrates, the fluorine shifts occur randomly.
Journal of Photochemistry and Photobiology A-chemistry, 2001
Addition of Fe(III) increases the number of strand breaks of plasmid DNA in aqueous solution unde... more Addition of Fe(III) increases the number of strand breaks of plasmid DNA in aqueous solution under gamma-radiolysis at room temperature and at 77 K. Low temperature radiolysis requires ca. 100 times higher radiation dose for the creation of comparable strand breaks due to the suppression of Fenton-type reactions. Room temperature radiolysis produces a relatively large number of multi-single strand breaks (ssb) and, on absorption of 100 Gy, less double-strand breaks (dsb), ca. 4%, while under cryogenic conditions at a dose of 10 kGy, are produced ca. 10% dsb for a similar total number of strand breaks. Fe(III) in its complex with EDTA exhibits small, but distinct damage to DNA even without irradiation, in comparison to the strong effect of Fe(II)/EDTA. Under our experimental conditions hydrogen peroxide does not influence the damage in a noticeable way in the presence of Fe(II) and Fe(III), although UV light exhibits a very strong effect on the addition of both Fe(III) and H2O2. In our system, iron forms complexes with EDTA and also is bound by other components. A molar excess of iron in relation to EDTA has no striking effect. The chelators seem to be responsible for creation of a reactive form of iron, able to produce reactive oxygen species in solutions containing dissolved air.
Journal of Liquid Chromatography & Related Technologies, 2010
ABSTRACT A new reversed-phase high performance liquid chromatographic (RP-HPLC) method is develop... more ABSTRACT A new reversed-phase high performance liquid chromatographic (RP-HPLC) method is developed and validated for the simultaneous determination of barbitone, allobarbitone, phenobarbitone, cyclobarbitone, hexobarbitone, pentobarbitone, secobarbitone and methohexitone compounds in a single analytical run. The method uses a Phenosphere C18 (150 mm × 4.6 mm; 5 μm) column and isocratic elution. The mobile phase consisted of a mixture of methanol-water (50:50, v/v), pumped at a flow rate of 1.0 mL/min. The UV detection is set at 254 nm. The method is validated with respect to accuracy, precision (repeatability and intermediate precision), specificity, linearity, range robustness and stability of analytical solutions. All the parameters examined met the current recommendations for bioanalytical method validation. The method is specific, simple, selective and reliable for routine use in quality control analysis of barbiturates raw materials for final product release.
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Papers by Tony K Bradshaw