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theses

The metabolism of living systems utilize many biosynthetic pathways in order to maintain homeostasis. These metabolic pathways involve multi-step chemical reactions to synthesize molecules and convert energy that are vital to life. These reactions, however, are too slow to support life. Nature has evolved enzymes, which are macromolecular catalysts, to speed up and catalyze these metabolic reactions. Enzymes are very sensitive to their surrounding environment, which can have profound effects on the enzymes function. In this thesis, the effects of different environments on the function of enzymes are explored. First, the effects of an anaerobic environment are shown to add a new catalytic function to an enzyme, allowing an FMN-bound diaphorase to act as a transhydrogenase, transferring a hydride between two critically important metabolic cofactors, NAD and NADP. Second, the effects of the storage conditions of the enzyme diaphorase are explored, and how its catalytic function changes from a dehydrogenase to that of an oxidase due to do partial unfolding of the enzyme during prolonged storage. Third, a DNA-crowded enzyme complex was developed to increase the local molecular crowding for affecting enzyme functions. The DNA-crowded enzyme nanoparticles are made by directly growing double-strand DNA on the enzymes surface via the hybridization chain reaction. The experimental results show that enzymes become more active and stable under a local DNA-crowded nano-environment.

ETD_8310

M.S.

Includes bibliographical references

by John Collins

doi:10.7282/T3RR228P

ETD graduate

The author owns the copyright to this work.