Biocatalytic potential of vanillin aminotransferase from Capsicum chinense.
BACKGROUND
The conversion of vanillin to vanillylamine is a key step in the biosynthetic route towards capsaicinoids in pungent cultivars of Capsicum sp. The reaction has previously been annotated to be catalysed by PAMT (putative aminotransferase; [GenBank: AAC78480.1, Swiss-Prot: O82521]), however, the enzyme has previously not been biochemically characterised in vitro.


RESULTS
The biochemical activity of the transaminase was confirmed by direct measurement of the reaction with purified recombinant enzyme. The enzyme accepted pyruvate, and oxaloacetate but not 2-oxoglutarate as co-substrate, which is in accordance with other characterised transaminases from the plant kingdom. The enzyme was also able to convert (S)-1-phenylethylamine into acetophenone with high stereo-selectivity. Additionally, it was shown to be active at a broad pH range.


CONCLUSIONS
We suggest PAMT to be renamed to VAMT (vanillin aminotransferase, abbreviation used in this study) as formation of vanillin from vanillylamine could be demonstrated. Furthermore, due to high stereoselectivity and activity at physiological pH, VAMT is a suitable candidate for biocatalytic transamination in a recombinant whole-cell system.
Nora
N
Weber
Abdelrahman
A
Ismail
Marie
M
Gorwa-Grauslund
Division of Applied Microbiology, Department of Chemistry, Lund University, SE-22100 Lund, Sweden. magnus.carlquist@tmb.lth.se.
Magnus
M
Carlquist
D001547:Benzaldehydes / Q000378:metabolism; D001596:Benzylamines / Q000378:metabolism; D055162:Biocatalysis; D002212:Capsicum / Q000201:enzymology*; D004926:Escherichia coli / Q000378:metabolism; D010940:Plant Proteins / Q000378:metabolism*; D000637:Transaminases / Q000378:metabolism*
D001547:Benzaldehydes; D001596:Benzylamines; D010940:Plant Proteins; C003754:vanillylamine; C100058:vanillin; D000637:Transaminases