Peroxidase-Like Reactivity at Iron-Chelation Sites in a Mesoporous Synthetic Melanin

Yijun Xie, Kelsey A. Krug, Kristine S. Cay, Mark Kalaj, Naneki C. McCallum, Zofia E. Siwicka, Zhao Wang, Nathan C. Gianneschi, Michael D. Burkart, Jeffrey D. Rinehart*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


High catalytic activity and substrate specificity make enzymes a rich source of inspiration for catalyst development. Co-opting the advantages of natural materials while tuning them to a modified form and purpose, however, is not a straightforward synthetic task. Polymerization of L-3,4-dihydroxyphenylalanine (L-DOPA) results in amorphous polymer nanoparticles that are similar in many ways to natural eumelanin. Herein, the authors introduce mesoporosity and iron ion chelation to synthesize a variant of the L-DOPA polymer with high peroxidase-like activity. Our results indicate catalytic reaction with peroxide under mildly acidic conditions (pH 5.4 and 6) with a greater maximum reaction velocity (Vmax) than horseradish peroxidase (HRP) at optimal pH 3.5–4.5. Comparison between Fe(III) and Fe(II) loading indicates that either can be used as a starting point to trigger reactivity, though Fe(II) loading leads to materials with twice the Vmax of the Fe(III)-loaded sample. The lack of catalyst degradation despite the redox changes and presence of radical species is consistent with the robust nature and redox versatility of polydopamine-based materials and demonstrates strong potential as a versatile redox-catalysis platform.

Original languageEnglish (US)
Pages (from-to)1483-1490
Number of pages8
JournalCCS Chemistry
Issue number3
StatePublished - Mar 2021


  • Catalysis
  • Iron ion chelation
  • L-DOPA
  • Mesoporosity
  • Peroxidase-like reactivity

ASJC Scopus subject areas

  • Chemistry(all)


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