Ostensible Enzyme Promiscuity: Alkene Cleavage by Peroxidases

Abstract

Enzyme promiscuity is generally accepted as the ability of an enzyme to catalyse alternate chemical reactions besides the 'natural' one. In this paper peroxidases were shown to catalyse the cleavage of a C=C double bond adjacent to an aromatic moiety for selected substrates at the expense of molecular oxygen at an acidic pH. It was clearly shown that the reaction occurs due to the presence of the enzyme; furthermore, the reactivity was clearly linked to the hemin moiety of the peroxidase. Comparison of the transformations catalysed by peroxidase and by hemin chloride revealed that these two reactions proceed equally fast; additional experiments confirmed that the peptide backbone was not obligatory for the reaction and only a single functional group of the enzyme was required, namely in this case the prosthetic group (hemin). Consequently, we propose to define such a promiscuous activity as 'ostensible enzyme promiscuity'. Thus, we call an activity that is catalysed by an enzyme 'ostensible enzyme promiscuity' if the reactivity can be tracked back to a single catalytic site, which on its own can already perform the reaction equally well in the absence of the peptide backbone.

Biocatalytic Promiscuity

“…The authors propose the term ostensible promiscuity for this observation. [39] This paper reviews enzyme catalytic promiscuity from a biocatalytic perspective. In the first part, the fundamentals of enzyme catalytic promiscuity are discussed.…”

Iron(III)‐porphyrin Complex FeTSPP: A Versatile Water‐soluble Catalyst for Oxidations in Organic Syntheses, Biorenewables Degradation and Environmental Applications

“…Interestingly, these peroxidase catalyzed reactions (according to Scheme 8) [22] do not proceed to a significant extent when the peroxidase is replaced by 1, which indicates that the Fe III -porphyrin-catalyzed transformation is highly chemo-selective (Scheme 7). The overoxidation of para-anisaldehyde 4 to its carboxylic acid was also not reported with 1 as a catalyst.…”

“…Kroutil et al found that here cleavage of the bond or dihydroxylation was observed in the biotransformation of trans-anethol 2 when using different types of peroxidases (Scheme 8). [22] In this reaction, besides para-anisaldehyde 4 as major product also the resulting 1,2-diol 6 was obtained.…”

Recent Advances in Rational Approaches for Enzyme Engineering

“…Care has also to be taken, that the apparent promiscuous reaction de facto stems from enzymatic catalysis and is not chemically catalyzed by a prosthetic group only [81] or by amino acids not related to an active site (e.g. EstB from B. gladioli , [82]) or from an apparent new reaction due to an overlooked change of the actual substrate e.g.…”