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|Title:||Bacterial Luciferase: Studies of Proteolytic Inactivation and Ligand Binding|
|Author(s):||Holzman, Thomas Fredric|
|Department / Program:||Biochemistry|
|Degree Granting Institution:||University of Illinois at Urbana-Champaign|
|Abstract:||The mechanism of proteolytic inactivation of luciferase was examined. Proteolytic inactivation in vitro was found to be concomittant with: (1) the loss of enzymatic activity; (2) altered enzyme affinity for substrate and product; (3) changes in enzyme secondary structure; and (4) the fragmentation of the (alpha) subunit into a discrete series of peptides, denoted the (gamma) and (delta) families. The region of the (alpha) subunit which was susceptible to proteolytic clipping was termed the Proteinase Labile Region and was observed to be a conserved structural feature in luciferases from distinct bacterial species. A preliminary study of the inactivation in vivo of the luciferase from Vibrio harveyi revealed the existence of isolatable antigenically cross-reactive peptide fragments bearing resemblance to peptides produced during proteolytic inactivation in vitro. The existence of fragments in vivo suggested that proteolysis in vitro may, in certain respects, parallel proteolytic events in vivo.
An affinity resin, useful for single-step purification of luciferase was synthesized. Chromatographic conditions for producing highly purified luciferases from Vibrio harveyi, Vibrio fischeri, and Photobacterium Phosphoreum were determined.
Examination of the interaction of luciferase with its aldehyde substrate revealed that the enzyme was subject to reversible inhibition by the aldehyde substrate. The occurrence of this inhibition explained several previous observations of enzyme kinetic behavior and suggested an alternative mechanistic model for the bioluminescence reaction pathway.
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1983.
|Date Available in IDEALS:||2014-12-15|