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Updated: Aug 19, 2026

Determination of the Photoisomerization Quantum Yield of a Hydrazone Photoswitch
Published on: February 7, 2022
Evidence for a pH-dependent isomerization of Clostridium oroticum dihydroorotase
Abstract:
Analytical gel permeation chromatography on both Sephadex and polyacrylamide columns shows that Clostridium oroticum dihydroorotase (L-5,6-dihydroorotate amidohydrolase, EC 3.5.2.3) undergoes a large decrease in molecular size when the pH is decreased from 8 to 6. The Stokes radius decreases from about 40 A to 36 A. Neither the molecular size nor kinetic properties are dependent on protein concentration. Thus, the decreased molecular size reflects a pH dependent isomerization of the enzyme.
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Stereoisomerism
Isomers are different chemical species that have the same chemical formula.
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