I think it’s strange that my favorite Beethoven symphony (Number 9, Number 9… ) is played around Christmastime. Additionally, this may not seem a propitious place from which to launch into a discussion of enzymatic bromination. And you would be right. Except that in both cases, I don’t really know what’s going on. Ode to Joy isn’t really religious and has nothing to do with snowmen or chestnuts or open fires. (Plus I don’t speak German. But I do hear that the translation is festive!)
In a similar way, we scientist types have only guesses as to how enzymes perform brominations. We think haloperoxidases mostly involve vague electron-pushing around peroxides, bromine anions, and metals (Fe or Mn) to make hypohalous acids, but beyond that… well… we dunno.
And uh I quote:
“Although a large number of halogenated organic compounds have been isolated, not much is known about the mechanisms by which fluorine, chlorine, bromine, or iodine atoms are incorporated into organic compounds.” [1]
Regardless of whether that was a horrible analogy, we do know much about electrophilic bromination in other contexts. For example, standard bromination conditions in organic chemistry commonly use NBS or bromine, and their mechanisms are well understood (think like Sophomore Organic Reactions) level of understanding). Hopefully someone can fill in the blanks someday with enzymatic halogenation. Although, it might be possible an understanding of Fenton chemistry would help… hmm. I’m certainly not an expert in this field, but I’d love to hear from someone who is!
[1] van Pee, K.-H.; Unversucht, S. Chemosphere 2003, 52, 299–312.
