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Electrochemical Characterization and Bioelectrocatalytic H 2 O 2 Sensing of Non‐Symbiotic Hexa‐Coordinated Sugar Beet Hemoglobins
Author(s) -
Sosna Maciej,
LeivaEriksson Nélida,
Bülow Leif,
Ferapontova Elena E.
Publication year - 2020
Publication title -
chemelectrochem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.182
H-Index - 59
ISSN - 2196-0216
DOI - 10.1002/celc.202000358
Subject(s) - electrochemistry , hexa , chemistry , sugar beet , heme , reactive oxygen species , crystallography , enzyme , biochemistry , biology , electrode , horticulture
The biological role of non‐symbiotic plant hemoglobins (Hbs) is not well understood. It may involve sensing and signaling of reactive nitrogen and oxygen species–a property that can be used in electrochemical sensing. Here, we electrochemically studied two novel non‐symbiotic Beta vulgaris Hbs: BvHb1.2 and BvHb2 expressed in E. coli . At pH 7, we observed close potentials of their Fe 2+/3+ hemes, −349 mV for BvHb1.2 and −345/−457 mV vs. Ag/AgCl for the “open” penta‐/“closed” hexa‐coordinated states of BvHb2. BvHbs bound and bioelectrocatalytically reduced O 2 and H 2 O 2 at potentials significantly exceeding their Fe 2+/3+ heme potentials. BvHb2, with the onset of H 2 O 2 reduction at 370 mV, enabled O 2 ‐interference‐free 10 μM H 2 O 2 detection at 0 mV, with a 87 nA μM −1 cm −2 sensitivity comparable to some peroxidases. The results underpin broad electrochemical applications of BvHbs in the electroanalysis of reactive species and in electrochemical biotransformations.