Kinetic insights into the peroxygenase activity of cellulose-active lytic polysaccharide monooxygenases (LPMOs)

• Published in: Nature communications Vol. 11; no. 1; p. 5786
• Main Authors: Kont, Riin, Bissaro, Bastien, Eijsink, Vincent G. H., Väljamäe, Priit
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 13-11-2020; Nature Publishing Group; Nature Portfolio
• Subjects: 631/45/603; 631/45/607/1168; 64; Biochemistry, Molecular Biology; Carbon cycle; Catalytic converters; Cellulose; Chitin; Competition; Enzymes; Humanities and Social Sciences; Hydrogen peroxide; Hydroxylation; Life Sciences; multidisciplinary; Oxidation; Polysaccharides; Saccharides; Science; Science (multidisciplinary); Side reactions; Substrates; Biocatalysis; Oxidoreductases
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-020-19561-8

Lytic polysaccharide monooxygenases (LPMOs) are widely distributed in Nature, where they catalyze the hydroxylation of glycosidic bonds in polysaccharides. Despite the importance of LPMOs in the global carbon cycle and in industrial biomass conversion, the catalytic properties of these monocopper enzymes remain enigmatic. Strikingly, there is a remarkable lack of kinetic data, likely due to a multitude of experimental challenges related to the insoluble nature of LPMO substrates, like cellulose and chitin, and to the occurrence of multiple side reactions. Here, we employed competition between well characterized reference enzymes and LPMOs for the H
2
O
2
co-substrate to kinetically characterize LPMO-catalyzed cellulose oxidation. LPMOs of both bacterial and fungal origin showed high peroxygenase efficiencies, with
k
cat
/
K
mH2O2
values in the order of 10
5
–10
6
 M
−1
s
−1
. Besides providing crucial insight into the cellulolytic peroxygenase reaction, these results show that LPMOs belonging to multiple families and active on multiple substrates are true peroxygenases.
Lytic polysaccharide monooxygenases (LPMOs) catalyze the hydroxylation of glycosidic bonds in polysaccharides, but the catalytic properties of these monocopper enzymes remain poorly characterized. Here authors employ competition between reference enzymes and LPMOs for the H
2
O
2
co-substrate to kinetically characterize LPMO-catalyzed cellulose oxidation.