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Biochemistry

Louisiana State University

Theses/Dissertations

Enzyme

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Full-Text Articles in Life Sciences

The Distinctive Regulatory Mechanisms Of Bacterial Acetyl-Coa Carboxylase, Alexandra Leigh Evans Sep 2018

The Distinctive Regulatory Mechanisms Of Bacterial Acetyl-Coa Carboxylase, Alexandra Leigh Evans

LSU Doctoral Dissertations

Metabolic Regulation is a complex system used to control cellular metabolism in response to conditions in the cell’s environment. For most enzymes, the cell can rely upon a minimal amount of regulation; however, critical enzymes, such as acetyl-CoA carboxylase, must be regulated at multiple levels. Acetyl-CoA carboxylase catalyzes the first committed step in fatty acid synthesis. In bacteria, acetyl-CoA carboxylase forms a complex of three subunits–biotin carboxylase, biotin carboxyl carrier protein, and carboxyltransferase–which catalyze the carboxylation of acetyl-CoA to form malonyl-CoA via two half-reactions. In the first half-reaction, biotin covalently linked to biotin carboxyl carrier protein is carboxylated by biotin …


On The Mechanism Of The Thiamine Catalyzed Reductive Dimerization Of Farnesyl Pyrophosphate To Squalene., Horatio D. Durst Jan 1967

On The Mechanism Of The Thiamine Catalyzed Reductive Dimerization Of Farnesyl Pyrophosphate To Squalene., Horatio D. Durst

LSU Historical Dissertations and Theses

The mechanism of the dimerization of farnesyl pyrophosphate to squalene was investigated in detail. Thiamine was found to catalyze this dimerization in yeast-soluble enzyme preparations. Removal of thiamine was found to cause the buildup of farnesyl pyrophosphate in the enzyme system. Derivatives of thiamine were tested to examine their effect on the dimerization reaction and were found to be inactive. It was found that extremely small amounts of thiamine enhance the formation of squalene while large concentrations inhibit the formation of squalene. Thiamine derivatives were synthesized to try to identify the intermediates in the enzyme system. These compounds are discussed …