Recent advances in heme biocatalysis engineering

Abstract

Heme enzymes have the potential to be widely used as biocatalysts due to their capability to perform a vast variety of oxidation reactions. In spite of their versatility, the application of heme enzymes was long time-limited for the industry due to their low activity and stability in large scale processes. The identification of novel natural biocatalysts and recent advances in protein engineering have led to new reactions with a high application potential. The latest creation of a serine-ligated mutant of BM3 showed an efficient transfer of reactive carbenes into C═C bonds of olefins reaching total turnover numbers of more than 60,000 and product titers of up to 27 g/L −1 . This prominent example shows that heme enzymes are becoming competitive to chemical syntheses while being already advantageous in terms of high yield, regioselectivity, stereoselectivity and environmentally friendly reaction conditions. Advances in reactor concepts and the influencing parameters on reaction performance are also under investigation resulting in improved productivities and increased stability of the heme biocatalytic systems. In this mini review, we briefly present the latest advancements in the field of heme enzymes towards increased reaction scope and applicability.

An Artificial Hemoprotein with Inducible Peroxidase‐ and Monooxygenase‐Like Activities

“…It is noteworthy that when the same reaction was performed in the presence of 18 O-labeled hydrogen peroxide, H 2 18 O 2 ,m ass spectrometry analysis of the obtained product confirmed the formation of 18 Ol abeled sulfoxide ( Figure S4) in line with an oxygen atom transfer from H 2 O 2 catalyzed by the Mn-TPP moiety.H owever, chiral HPLC analysiso ft he reactionm ixture showedt he formation of racemic sulfoxide.…”

“…As a consequence, man-made P450s have becomef or decades the focus of intensiver esearch. Twol ines have been undertaken: i) The protein engineering of naturally occurring P450s [1,2] and ii)the identification of artificial biomimetic de novo constructs. [3] Artificial metalloenzymes (ArMs) mimicking cytochromes P450 are mostly based on synthetic metalloporphyrinst hat have long proven to be efficient catalysts for oxidation reactions in organic solvents.…”

Investigation of Vitamin D2 and Vitamin D3 Hydroxylation by Kutzneria albida

“…Genome sequencing of K. albida revealed that 14 % of the chromosome is composed of secondary metabolism gene clusters, [29] which complies with a large number of P450s present in this strain (Table S1). Previous screening of K. albida showed a broad hydroxylation potential in the conversion of seven tested pharmaceutical compounds among other complex molecules, such as cyclosporine A, tamoxifen, and ritonavir [30] . Categorization of the 50 encoded P450s in superfamilies revealed the CYP107 family, the family of the known VD 3 hydroxylase Vdh from P. autotrophica , as most abundant (Table S2) [31] …”

“…These results suggest that either high concentrations of dissolved VD 2 and VD 3 or the solubilizers themselves have an inhibitory or toxic effect on the biocatalyst K. albida and therefore do not promote a better substrate conversion in the biotransformation. Inhibitory or toxic effects of the substrate or product on the biocatalyst as limiting factor for a biotransformation have been analyzed in literature before [30] . To overcome such limitations, the use of cyclodextrins has been discussed [33] .…”

Identification and Expression of New Unspecific Peroxygenases – Recent Advances, Challenges and Opportunities

“…Biotransformations are used in the pharmaceutical industry to replace complex chemical syntheses, e.g., to obtain drug metabolites for pharmacological activity and toxicity studies ( Rosenthal and Lütz, 2018 ). Especially, the large group of heme enzymes harbors versatile biocatalysts, which oxidize non-activated C-H bonds regio- and stereospecifically under mild reaction conditions ( Schmitz et al, 2019a ). In 2004, a new type of heme-thiolate enzyme with mono(per)oxygenase activity was discovered in the basidiomycetous fungus Agrocybe aegerita catalyzing a broad range of oxidative transformations ( Ullrich et al, 2004 ).…”