Molecular probes for the evaluation of three isomerase enzyme mechanisms in secondary metabolism

Isomerization;Enzymology;Metabolism, Secondary

Nasomjai, Pitak ; O'Hagan, David ; O'Hagan, David

University:University of St Andrews

Department:Chemistry (School of)

关键词: Isomerization;    Enzymology;    Metabolism, Secondary;   

Others  :  https://research-repository.st-andrews.ac.uk/bitstream/handle/10023/866/Pitak%20Nasomjai%20PhD%20thesis.pdf?sequence=6&isAllowed=y

来源: DR-NTU

【 摘 要 】

This thesis is focused on an investigation of the mechanisms of three enzymatically mediated carbon skeleton isomerisation reactions. Chapter 1 provides an overview of some representative examples of the carbon skeleton rearrangement reactions in enzymology.Chapter 2 describes the preparation and use of fluorolittorines to explore the mechanism of the rearrangement of the tropane alkaloid littorine to hyoscyamine which is a reaction mediated by the cytochrome P450 enzyme. Chapter 3 describes the synthesis of D-ribose-1-phosphonates and the cyclic phosphonates (phostone) that are candidate inhibitors of the enzymatic isomerisation of 5-fluoro-5-deoxy-ribose-1-phosphate (5-FDRP) to 5-fluoro-5-deoxy-ribulose-1-phosphate (5-FDRulP), an important step in fluorometabolite biosynthesis pathway in Streptomyces cattleya. Chapter 4 describes the synthesis of 5-hydroxy-3,4-dioxohexylphosphonate and [5-13C]-5-hydroxy-3,4-dioxohexylphosphonate. These compounds are proposed as candidates for the transition state of the retro-aldol/aldol mechanism of the enzymatic isomerisation of 1-deoxy-D-xylulose-5-phosphate (DXP) to 2-C-methylerythitol-phophate-2-phosphate (MEP) in the biosynthesis of isopentenyl pyrophosphate (IPP) and dimethylallyl pyrophosphate (DMAPP). The influence of pH on tautomerisation of [5-13C]-5-hydroxy-3,4-dioxohexylphosphonate is also described.Chapter 5 describes the general chemical and biochemical methodologies utilised in this research project.