Date of Award:
5-1973
Document Type:
Dissertation
Degree Name:
Doctor of Philosophy (PhD)
Department:
Plants, Soils, and Climate
Department name when degree awarded
Plant Nutrition and Biochemistry
Committee Chair(s)
Gene W. Miller
Committee
Gene W. Miller
Committee
Bruce F. Burnham
Committee
George W. Cochran
Committee
Raymond Lynn
Committee
D. K. Salunkhe
Committee
B. F. Burnham
Abstract
Uroporphyrinogen decarboxylase which catalyses the formation of coproporphyrinogen from uroporphyrinogen is located in the soluble fraction of tobacco leaves and was purified 72 fold through ammonium sulphate precipitation and calcium phosphate gel adsorption.
Kinetic studies indicated that the apparent Michaelis constant was 1 x 10-6 for uroporphyrinogen III (pH 6.5; 37° C). Uroporphyrinogen III served as a much better substrate than uroporphyrinogen I under the standard conditions of this study.
Enzyme activity was inhibited by thiol reagents and heavy divalent cations.
Both chloride and fluoride salts inhibited the formation of coproporphyrinogen from uroporphyrinogen.
Enzyme activity was inhibited by several metals and was stimulated by some chelating agents.
Recommended Citation
Chen, Tsung-chiang, "Studies of Porphyrin Biosynthesis in Higher Plants" (1973). All Graduate Theses and Dissertations, Spring 1920 to Summer 2023. 9103.
https://digitalcommons.usu.edu/etd/9103
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