Date of Award
11-1983
Degree Type
Thesis
Degree Name
Doctor of Philosophy (PhD)
Department
Chemistry
Supervisor
Professor I.D. Spenser
Abstract
The steric course of decarboxylation of L-ornithine to yield putrescine, catalysed by L-ornithine decarboxylase (E.C. 4.1.1 17) of E. coli, and of L-arginine to yield agmatine, catalysed by L-arginine decarboxylase (E.C. 4.1.1.19) of E. coli, is investigated by deuterium labelling. Replacement of the carboxyl group by a solvent derived proton occurs with retention of configuration in each case.
In conflict with an earlier report, incubation of cadaverine in deuterium oxide in the presence of L-lysine decarboxylase (E.C. 4.1.1.18) of B. cadaveris did not lead to entry of deuterium into the α-position of cadaverine. Likewise, L-ornithine decarboxylase did not catalyse exchange of the α-hydrogen of putrescine, nor did L-arginine decarboxylase catalyse such an exchange in agmatine.
The stereochemistry of hydrogen abstraction in the conversion of cadaverine into 'Δ'-piperidine, of putrescine into Δ'-pyrroline, and of agmatine into 4-guanidinobutanal, catalysed by hog kidney diamine oxidase (E.C. 1.4.3.6) is investigated. The Si-hydrogen from C-1 of the substrate is removed while the Re-hydrogen from C-1 of the substrate is maintained at the Sp² carbon atom of each of the products.
The diamine oxidase catalysed oxidative deamination of cadaverine takes place without detectable isotope effect, while an intramolecular primary hydrogen-deuterium isotope effect (kHsi./kDsi = 4) is observed in the diamine oxidase catalysed oxidation of putrescine.
Recommended Citation
Richards, James Clare, "The Stereochemistry of Enzymic Reactions at Prochiral Centres" (1983). Open Access Dissertations and Theses. Paper 1430.
http://digitalcommons.mcmaster.ca/opendissertations/1430