Phorbol 12,13-dibutyrate (PDBu) is a phorbol ester which is one of the constituents of croton oil. As an activator of protein kinase C, it is a weak tumor promoter compared to 12-O-tetradecanoylphorbol-13-acetate. Tritiated PDBu has been used to study the way that phorbol esters bind to the protein kinase C receptor.
Metabolism The enzyme phorbol-diester hydrolase originally characterised from murine liver hydrolyses PDBu to remove one specific butyrate ester, giving phorbol 13-butanoate and butyric acid. It also acts on 12-O-tetradecanoylphorbol-13-acetate.
Only phorbol diesters are tumor promoters, so this reaction inactivates them.
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