Abstract
Recently, crystalized mouse ketimine reductase/CRYM complexed with NADPH was found to have pyruvate bound in its active site. We demonstrate that the enzyme binds α-keto acids, such as pyruvate, in solution, and catalyzes the formation of N-alkyl-amino acids from alkylamines and α-keto acids (via reduction of imine intermediates), but at concentrations of these compounds not expected to be encountered in vivo. These findings confirm that, mechanistically, ketimine reductase/CRYM acts as a classical imine reductase and may explain the finding of bound pyruvate in the crystallized protein.
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Abbreviations
- CRYM:
-
μ-Crystallin
- DTT:
-
Dithiothreitol
- LCMS:
-
Liquid chromatography-mass spectrometry
- P2C:
-
Δ1-Piperideine-2-carboxylate
- T3 :
-
3,5,3′-Triiodothyronine
- P2CR:
-
Δ1-Piperideine-2-carboxylate reductase
- TLC:
-
Thin layer chromatography
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Hallen, A., Cooper, A.J.L., Smith, J.R. et al. Ketimine reductase/CRYM catalyzes reductive alkylamination of α-keto acids, confirming its function as an imine reductase. Amino Acids 47, 2457–2461 (2015). https://doi.org/10.1007/s00726-015-2044-8
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DOI: https://doi.org/10.1007/s00726-015-2044-8