Cryptoregiochemistry

{{Short description|Oxidative attack site}}

Cryptoregiochemistry refers to the site of initial oxidative attack in double bond formation by enzymes such as fatty acid desaturases.{{Cite book |last=Begley |first=Tadhg P. |url=https://books.google.com/books?id=i3cTAQAAMAAJ |title=Wiley Encyclopedia of Chemical Biology, Volume 2 |date=2009-02-03 |publisher=Wiley |isbn=978-0-470-47018-3 |pages=3–6 |language=en}} This is a mechanistic parameter that is usually determined through the use of kinetic isotope effect experiments, based on the premise that the initial C-H bond cleavage step should be energetically more difficult and therefore more sensitive to isotopic substitution than the second C-H bond breaking step.