Kinetic Analysis of PRMT1 Reveals Multifactorial Processivity and a Sequential Ordered Mechanism |
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| Authors: | Jennifer I. Brown Dr. Timo Koopmans Jolinde van Strien Dr. Nathaniel I. Martin Dr. Adam Frankel |
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| Affiliation: | 1. Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, BC, Canada;2. Department of Chemical Biology and Drug Discovery, Utrecht Institute for Pharmaceutical Sciences, University of Utrecht, Utrecht, The Netherlands;3. Leiden Institute for Chemistry, Gorlaeus Laboratories, Leiden, The Netherlands |
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| Abstract: | Arginine methylation is a prevalent post‐translational modification in eukaryotic cells. Two significant debates exist within the field: do these enzymes dimethylate their substrates in a processive or distributive manner, and do these enzymes operate using a random or sequential method of bisubstrate binding? We revealed that human protein arginine N‐methyltransferase 1 (PRMT1) enzyme kinetics are dependent on substrate sequence. Further, peptides containing an Nη‐hydroxyarginine generally demonstrated substrate inhibition and had improved KM values, which evoked a possible role in inhibitor design. We also revealed that the perceived degree of enzyme processivity is a function of both cofactor and enzyme concentration, suggesting that previous conclusions about PRMT sequential methyl transfer mechanisms require reassessment. Finally, we demonstrated a sequential ordered Bi–Bi kinetic mechanism for PRMT1, based on steady‐state kinetic analysis. Together, our data indicate a PRMT1 mechanism of action and processivity that might also extend to other functionally and structurally conserved PRMTs. |
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| Keywords: | enzyme catalysis kinetics peptides protein modifications transferases |
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