Enzyme-catalyzed polymerization of 8-hydroxyquinoline-5-sulfonate by in situ nuclear magnetic resonance spectroscopy
✍ Scribed by K. Shridhara Alva; Lynne Samuelson; Jayant Kumar; Sukant Tripathy; Ashok L. Cholli
- Publisher
- John Wiley and Sons
- Year
- 1998
- Tongue
- English
- Weight
- 187 KB
- Volume
- 70
- Category
- Article
- ISSN
- 0021-8995
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✦ Synopsis
In this report, we describe the use of in situ NMR spectroscopy to elucidate the mechanism of horseradish peroxidase-catalyzed oxidative free-radical coupling of phenols. We demonstrate the potential of the technique for the polymerization of 8-hydroxyquinoline-5-sulfonate (HQS). Based on the structural changes, we establish the involvement of ortho-and para-position protons (to the hydroxyl group) in the oxidative free-radical coupling polymerization with their relative preferences. For example, in HQS, we establish that the positions 2, 4, and 7 are involved in the chemical bonding with the order of preference being 7 Ն 2 Ͼ 4. Analyses of 13 C-NMR data suggest the formation of COC-and COOOC-type coupling bonds during enzymatic polymerization.