Thesis (Master of Applied Science in Chemistry)--Cape Peninsula University of Technology, 2018. / The prediction of the single crystal structure that will form due to the combination of two or more compounds to form a multicomponent crystal is one of the important areas of research in crystal engineering. Since these compounds display different properties when combined as a single crystal, knowledge of synthesis and design of the resulting compound is essential. The formation of a multicomponent crystal, such as a salt or a cocrystal generally depends on the complementarity of the functional groups present on both components. This means that basicity and acidity of the functional groups present on the selected compounds need to be considered. This study investigated salts and cocrystals of 3-chloro-4-hydroxyphenylacetic acid (CHPAA) using the ΔpKa rule. The calculated ΔpKa values were recorded and correlated with the experimental analysis in predicting the outcome of the crystallisation experiments ie. salt or cocrystal formation. This was further confirmed by the analysis of the C-O bond lengths found in the crystal structures. Salts were obtained by combinations of CHPAA with several organic bases (co-formers) such as diethylamine, dibutylamine, 2-aminopyridine, 2-amino-4-methylpyridine, 2-amino-6-methylpyridine and 4-dimethylaminopyridine. The calculated ΔpKa values were within the range of salt formation. Furthermore, the experimental analysis also showed that all resulting compounds were salts. Cocrystals were obtained by reactions of nicotinamide, isonicotinamide, phenazine and 4,4’-bipyridine with CHPAA. Again, the calculated ΔpKa values predicted cocrystals as the new solid forms. Experimental analysis carried out also confirmed cocrystal formation. For all resulting compounds, the comparison of intermolecular interactions as well as supramolecular synthons were reported. All compounds were synthesised by slow evaporation techniques using various organic solvents and characterised by single crystal X-ray diffraction, powder X-ray diffraction, thermal analysis and Fourier transformer infrared spectroscopy. From the structural analysis, it was found that all resulting structures displayed strong N-H•••O and O-H•••O intermolecular interactions including weak interactions of C-H•••Cl, C-H•••O and C-H•••π for a few of the structures. Furthermore, comparison of the crystal structures showed that no packing arrangement similarity existed between the compounds.

by Vincent Wing-Fai Tai. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1993. / Includes bibliographical references (leaves 79-83). / Acknowledgements --- p.i / Contents --- p.ii / Abstract --- p.iii / Abbreviations --- p.iv / Chapter I --- Introduction / Chapter I-1 --- General Background --- p.1 / Chapter I-2 --- Review on Epoxycyclohexanes --- p.2 / Chapter I-3 --- Mechanistic Aspect of Glycosidase Inhibitors --- p.5 / Chapter I-4 --- Previous Synthesis of cyclophellitol and its diastereoisomers 1-4 --- p.12 / Chapter II --- Results and Discussion / Chapter II-l --- General Strategy --- p.19 / Chapter II-2 --- Synthesis of the diol 57 --- p.21 / Chapter II-3 --- Synthesis of the allylic alcohol 54 --- p.25 / Chapter II-4 --- "Synthesis of Cyclophellitol 1 and its (lR,6S)-diastereoisomer 2" --- p.29 / Chapter II-5 --- "Synthesis of the (2S)- and (lR,2S,6S)-diasteroeisomers 3 and 4" --- p.34 / Chapter II-6 --- Comments on the MCPBA Epoxidation --- p.37 / Chapter II-7 --- Synthesis of the Epoxy Analogues of Cyclophellitol 104 and 105. --- p.40 / Chapter II-8 --- Results of biological assays --- p.43 / Chapter III --- Conclusion --- p.48 / Chapter IV --- Experimental --- p.50 / Chapter V --- References --- p.79 / Chapter VI --- Spectra --- p.84

Yeung, Ching Yee. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (leaves 112-122). / Abstracts in English and Chinese. / Acknowledgments --- p.I / Abstract --- p.II / 摘要 --- p.III / Content --- p.IV / Abbreviations and symbols --- p.XI / List of tables and figures --- p.XV / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Acylphosphatase --- p.1 / Chapter 1.2 --- Human acylphosphatase --- p.4 / Chapter 1.3 --- Hyperthermophilic Pyrococcus horikoshii acylphosphatase --- p.5 / Chapter 1.4 --- Human common-type acylphosphatase as a mesophilic homologue of Pyrococcus horikoshii acylphosphatase --- p.8 / Chapter 1.5 --- Enzyme-substrate interaction of acylphosphatase --- p.9 / Chapter Chapter 2 --- Materials and methods --- p.10 / Chapter 2.1 --- Preparation of Escherichia coli competent cells --- p.10 / Chapter 2.2 --- SDS-polyacrylamide gel electrophoresis --- p.11 / Chapter 2.2.1 --- Preparation of polyacrylamide gel --- p.11 / Chapter 2.2.2 --- SDS-polyacrylamide gel electrophoresis (SDS-PAGE) --- p.12 / Chapter 2.2.3 --- Staining of protein in polyacrylamide gel by Coommassie Brillant Blue R250 --- p.12 / Chapter 2.3 --- Expression and purification of Protein --- p.13 / Chapter 2.3.1 --- "General bacterial culture, harvesting and lysis" --- p.13 / Chapter 2.3.2 --- Purification of acylphosphatase --- p.14 / Chapter 2.3.2.1 --- Ion-exchange chromatography --- p.14 / Chapter 2.3.2.2 --- Size excision chromatography --- p.15 / Chapter 2.3.3 --- Protein concentration determination --- p.16 / Chapter 2.4 --- X-ray crystallography --- p.17 / Chapter 2.4.1 --- Crystallization of Hu CT AcP --- p.17 / Chapter 2.4.2 --- Model building and structural refinement --- p.18 / Chapter 2.4.3 --- Crystallization of Hu CT AcP -substate analogue complex --- p.19 / Chapter 2.5 --- Enzymatic Assay --- p.21 / Chapter 2.5.1 --- Preparation of benzoyl phosphate --- p.21 / Chapter 2.5.2 --- Purity check of the BP synthesized --- p.22 / Chapter 2.5.3 --- Determination of kinetic parameters of Hu CT AcP --- p.25 / Chapter 2.5.4 --- Determination of Ki value of substrate analogue --- p.27 / Chapter 2.6 --- Isothermal titration calorimetry --- p.28 / Chapter 2.7 --- Reagents and Buffers --- p.30 / Chapter 2.7.1 --- Reagent for competent cell preparation --- p.30 / Chapter 2.7.2 --- Media for bacterial culture --- p.31 / Chapter 2.7.3 --- Reagent for SDS-PAGE --- p.32 / Chapter 2.7.4 --- Buffer for AcP purification --- p.33 / Chapter 2.7.5 --- Buffer for enzymatic assay and ITC --- p.33 / Chapter Chapter 3 --- Structural determination of human common-type acylphosphatase --- p.34 / Chapter 3.1 --- Introduction --- p.34 / Chapter 3.2 --- Expression and purification of Hu CT AcP --- p.35 / Chapter 3.3 --- Structure of Hu CT AcP was determined by X-ray crystallography --- p.37 / Chapter 3.3.1 --- Crystallization of Hu CT AcP --- p.37 / Chapter 3.3.2 --- Model building and structural refinement --- p.41 / Chapter 3.3.3 --- Hu CT AcP shares a same α/β sandwich fold structure as other AcP --- p.43 / Chapter 3.4 --- Discussion --- p.46 / Chapter 3.4.1 --- Active site structure of Hu CT AcP is the same as those of bovine CT AcP and Ph AcP --- p.46 / Chapter 3.4.2 --- Absence of salt bridge between the active site residue and the C-terminal may contribute to the higher catalytic efficiency of Hu CT AcP --- p.52 / Chapter Chapter 4 --- Characterization of interaction between acylphosphatase and substrate analogues --- p.56 / Chapter 4.1 --- Introduction --- p.56 / Chapter 4.2 --- Selected substrate analogues --- p.57 / Chapter 4.3 --- Characterization of AcP-substrate analogue interaction by enzymatic assay --- p.59 / Chapter 4.3.1 --- Enzyme kinetics of Hu CT AcP was determined by the continuous optical assay of BP hydrolysis --- p.59 / Chapter 4.3.2 --- Substrate analogues were found to be competitive inhibitor to the AcP-catalyzed BP hydrolysis --- p.61 / Chapter 4.3.3 --- S-BA was the best competitive inhibitor against AcP-catalyzed BP hydrolysis --- p.64 / Chapter 4.3.4 --- S-BA was shown to be a competitive inhibitor for both Hu CT and Ph AcP --- p.66 / Chapter 4.4 --- Characterization of AcP-substrate analogue interaction by thermodynamic study --- p.68 / Chapter 4.4.1 --- Enthalpy change was observed for the association between substrate analogue and AcP --- p.68 / Chapter 4.4.2 --- S-BA was shown to bind Hu CT AcP with high affinity in ITC study --- p.68 / Chapter 4.5 --- S-BA was found to be the best substrate analogue for AcP --- p.72 / Chapter 4.6 --- Discussion --- p.73 / Chapter 4.6.1 --- Structure-affinity study of substrate analogue reveals chemical structures essential to interaction with AcP --- p.73 / Chapter 4.6.2 --- Structure-affinity study of substrate analogues is consistent with docking model of AcP with acetyl phosphate --- p.75 / Chapter 4.6.3 --- Validation of docking model by crystal complex structure --- p.78 / Chapter 4.6.4 --- Structural basis of substrate inhibition in Hu CT AcP --- p.80 / Chapter 4.6.4.1 --- Substrate inhibition is observed in Hu CT AcP --- p.80 / Chapter 4.6.4.2 --- Non-productive binding and substrate inhibition in AcP --- p.80 / Chapter Chapter 5 --- Investigation on the effect of salt bridge on acylphosphatase- substrate analogue interaction --- p.84 / Chapter 5.1 --- Introduction --- p.84 / Chapter 5.2 --- Thermodynamic study on the binding of S-BA with AcPs --- p.87 / Chapter 5.2.1 --- Determination of thermodynamic parameters of interaction between AcP and substrate analogue --- p.87 / Chapter 5.2.2 --- Determination of thermodynamic parameters as a function of temperature --- p.90 / Chapter 5.3 --- Discussion --- p.93 / Chapter 5.3.1 --- The presence of salt bridge leads to a reduced flexibility at the substrate binding active site --- p.93 / Chapter 5.3.2 --- The single salt bridge reduces the flexibility of active site in both study on thermodynamics of binding and thermodynamics of activation --- p.94 / Chapter 5.3.3 --- Temperature dependence of the thermodynamic parameters and heat capacity change ΔCp --- p.97 / Chapter 5.3.3.1 --- Change in heat capacity reveals the nature of the complex interface --- p.97 / Chapter 5.3.3.2 --- Determination of heat capacity change ΔCp --- p.98 / Chapter Chapter 6 --- Structural determination of acylphosphatase-substrate analogue complex --- p.102 / Chapter 6.1 --- Introduction --- p.102 / Chapter 6.2 --- Soaking and cocrystallization failed to give cocrystal structure of Hu CT AcP and S-BA --- p.103 / Chapter 6.4 --- Discussion --- p.106 / Chapter 6.4.1 --- Hu CT AcP and S-BA is not compatible with cocrystal formation --- p.106 / Chapter 6.5 --- Future prospect --- p.107 / Chapter 6.5.1 --- Structure determination by NMR spectroscopy --- p.107 / Chapter 6.5.2 --- Structure determination of AcP with aluminofluoride complexes --- p.108 / Chapter Chapter 7 --- Conclusion --- p.109 / Reference --- p.112

No description available.

Rice is an important dietary grain but may be difficult to fortify with water-soluble vitamins due to the losses incurred during processing and preparation. Edible coatings can offer reasonable protection against folate processing losses in fortified rice, in particular pectin (Shrestha, 2003). However, pectin, an indigestible fibre, may entrap or bind added folate, decreasing its absorption efficiency. Healthy volunteers (n=26, 18-39 yrs) received oral 400??g [13C5]PteGlu doses in three separate test meals in randomized cross-over trials as follows: 1) aqueous 2) 200g white rice and 3) 200g of pectin-coated rice premix. A plasma AUC0-8 was conducted (0, 1, 2, 5 and 8 hrs postprandial). Subjects followed a low folate basal diet (112??12 ??g/day) - verified using L.casei microbiological assay - during the AUC and for 24 hours prior. Optimisation of the pectin-coated rice premix gave folic acid coating and cooking losses of 33.5% and 15.5% respectively. The mean test dose error per 400??g folic acid was ?? 26 ??g. Single- or tri- enzyme extraction of fortified rice extracts did not significantly increase the mean assayable folate content compared to the mean folic acid content. The levels of plasma [13C5]5-methyl-THF, [13C5]PteGlu and 5-methyl-THF were quantified using a validated HPLC-tandem MS method. The calibration curves indicated good response linearity in the 0-100 ng/mL range (R2&gt0.9978). Inter- and intra-assay variation of 5-methyl-THF (100 ng/mL) was 6.9% (n=6) and 5.2% (n=4) respectively. The mean recovery of 5, 20 and 50 ng/mL 5-methyl-THF in spiked plasma extracts was 98.6 ?? 8.7%, 89.3 ?? 2.8% and 92.6 ?? 3.7% (n=3) respectively. Standard Reference Material-1846, infant formula (129??28 ??g/100g) was measured at 110 ?? 15 ??g folic acid/100g. The relative bioavailability of the folic acid in meals 2 and 3 was measured by comparing their [13C5]5-methyl-THF AUC???s relative to meal 1. The relative bioavailabilities (Mean % ?? CI) of meals 2 and 3 were 86.5 ?? 4.6 % and 68.7 ?? 5.4 % respectively. It appears the pectin coat moderately reduces short-term folic acid bioavailability. These studies define the basis for calculating the amount of folic acid to be added to rice so that an adequate amount can be absorbed after coating and cooking losses. Pectin coatings may be a useful means of increasing the folate status of populations that rely heavily on rice as a staple.

No description available.

Graduation date: 1966

Graduation date: 2005

Thesis (M.S.)--Oregon State University, 1983. / Typescript (photocopy). Includes bibliographical references (leaves 29-33). Also available on the World Wide Web.

Thesis (M.S.)--Oregon State University, 1984. / Typescript (photocopy). Includes bibliographical references (leaves 54-60). Also available on the World Wide Web.