Dehaloperoxidase (DHP) from Amphitrite ornata is an active oxygen-binding multi-functional hemoglobin. This catalytic marine globin can exhibit peroxygenase, oxygenase, and oxidase activities with various substrates such as haloindoles, nitrophenols, and pyrroles. Most recently, it was inquired on as to how DHP acts with p-guaiacols as its substrate. Using a combination of spectroscopic and spectrometric techniques (UV/vis, HPLC, LC-MS), we report here on the reactivity of DHP with this new class of p-guaiacol (4-methoxyphenol) substrate. When DHP was reacted in the presence of H2O2 with 2-nitro, 2-bromo, 3-bromo, and p-guaiacol, the substrate turnover was determined using HPLC, and major products were identified using LC-MS. Overall, the substrates reacted similarly with the ferric and oxyferrous forms of DHP with &gt;90% turnover. Of the panel of controls and mechanistic probes used, 4-bromophenol was the only to cause a significant effect on turnover, causing a one-fourth decrease. Using Density Functional Theory (DFT), reaction thermodynamics were studied and theoretical pKa values were calculated using B3LYP/ 6311++G (d, p).

Mechanistic studies of para-guaiacols as new substrates for dehaloperoxidase from Amphitrite ornata

255th National Meeting (2018)

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