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Title: An investigation of the reactions of pyridoxal-phosphate with amino-acids and metal ions
Author: Mastrantonis, Joanna
Awarding Body: University of London
Current Institution: Royal Holloway, University of London
Date of Award: 1982
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The reactions of pyridoxal phosphate with amino acids and metal ions have been investigated. The kinetics have been studied by spectrophotometric and by polarimetric techniques. The reaction products were analysed by chromatography (paper and liquid column). 71Ga, 27Al, 115In, 1H, 31P and 13C n.m.r. techniques have been used to identify the structures of the complexes in solution. The rates of formation of Cu2+-SB and Zn2+-SB complexes were dependent on the concentration of pyridoxal phosphate and the amino acid, the metal concentration had no effect on the rate showing that the metal traps the Schiff base. Cu2+ was the only metal to cause racemization of the aldimine complex formed from L-glutamate and pyridoxal phosphate. No Schiff base of any other amino acid was racemized by Cu2+ or by any other metal. The rates of formation of M3+-SB complexes are dependent, however, on the concentrations of the M3+ ions when these are low. Multinuclear n.m.r. studies show that the M3+-PLP complexes are symmetrical in acid media and coordination is through the phosphate group. 13C n.m.r. shows that M3+-SB complexes are asymmetrical species. M3+ are never coordinated through the phosphate in SB complexes. The possibilities of establishing the stoichiometry mode of bonding and symmetry of M3+ complexes from the spectral widths of 71Ga and 115In m.m.r. spectroscopy are discussed. 31P and 27Al n.m.r. has also been studied and types of coordination have been suggested from numbers and chemical shifts and widths of the observed signals.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: Physical Chemistry