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Full-Text Articles in Physical Sciences and Mathematics

Kinetic Evaluation Of Human Cloned Coproporphyrinogen Oxidase Using A Ring Isomer Of The Natural Substrate, Marjorie A. Jones, Christopher L. Cooper, Timothy D. Lash Nov 2005

Kinetic Evaluation Of Human Cloned Coproporphyrinogen Oxidase Using A Ring Isomer Of The Natural Substrate, Marjorie A. Jones, Christopher L. Cooper, Timothy D. Lash

Faculty Publications – Chemistry

Background: The enzyme coproporphyrinogen oxidase (copro'gen oxidase) converts coproporphyrinogen-Ill (GIII) to protoporphyrinogen-IX via an intermediary monovinyl porphyrinogen. The A ring isomer coproporphyrinogen-IV (C-IV) has previously been shown to be a substrate for copro'gen oxidase derived from avian erythrocytes. In contrast to the authentic substrate (GIII) where only a small amount of the monovinyl intermediate is detected, C-IV gives rise to a monovinyl intermediate that accumulates before being converted to an isomer of protoporphyrinogen-IX. No kinetic studies have been carried out using the purified human copro'gen oxidase to evaluate its ability to process both the authentic substrate as well as analogs. …


Microscopic Theory Of The Low Frequency Raman Modes In Germanium Nanocrystals, Shang-Fen Ren, Peter Y. Yu May 2005

Microscopic Theory Of The Low Frequency Raman Modes In Germanium Nanocrystals, Shang-Fen Ren, Peter Y. Yu

Faculty publications – Physics

We have studied the Raman intensities of low-frequency phonon modes in germanium (Ge) nanocrystals (NC) with varying sizes by using a microscopic valence force field model. The results are compared with the predictions of the continuum model of Lamb using a projection method. We found that the l=0 spheroidal Lamb modes are Raman active in the parallel polarization scattering geometry, while the l=2 spheroidal Lamb modes are active in the crossed polarization geometry. This result agrees with the group theory prediction that the torsional Lamb modes are not Raman active, but is in disagreement with the identification of torsional Lamb …