| Summary: | The biosynthesis of polyamines is a topic of current interest. A number of methods for the isolation and analysis of these polyamines have been described in the literature. However, the stereochemical course of the biosynthesis of these polyamines is still undefined. After a general introduction to the importance of the polyamines in living cells (Chapter 1), Chapter 2 outlines the materials, methods and the instruments used in this project. In Chapter 3, isolation, separation and analysis of the polyamines via their phenylaminothiocarbonyl derivatives is described. The 1H and 13C n.m.r. spectroscopic analyses of these derivatives are also described. The synthesis of amino acids specifically or stereospecifically labelled with deuterium after some modifications of a literature method, are described in Chapter 4. The biosynthesis of spermidine from putrescine and 2H or 13C labelled methionine is described in Chapter 5. This Chapter demonstrates the incorporation of the 3-aminopropyl group of the labelled methionine as an intact unit into spermidine. The condensation reaction between ethanal and 1,3-diaminopropane is described in Chapter 6. The products of such condensations, namely hexahydropyrimidine compounds were acetylated. Full 1H n.m.r. analysis for the hexahydropyrimidines and their acetyl derivatives are described. Decouplings in some cases are necessary to assure the assignment of the spectrum. The stereochemistry of spermidine synthase is studied in Chapter 7. In this Chapter, hexahydropyrimidine derivatives of stereospecifically labelled biosynthetic [1',2'-2H2]spermidines were used to define the relative configurations at the labelled methylenes (by 400 MHz 1H n.m.r. spectroscopy). A definite judgement of the stereochemistry of spermidine synthase necessitated the synthesis of stereospecifically labelled [1',2'-2H2]spermidines. The hexahydropyrimidines of these spermidines are compared with those of the biosynthetic spermidines obtained from stereospecifically labelled methionines by the action of E. coli cells. The outcome of this work demonstrates the inversion of configuration at C-3 of the 3-aminopropyl group (originally C-4 of methionine) after its incorporation into spermidine.
|
|---|
