Study of the (S)-hydroxynitrile lyase from Hevea brasiliensis: mechanistic implications.
Investigations of the (S)-selective hydroxynitrile lyase from Hevea brasiliensis were performed by electrospray mass spectroscopy, (1)H-NMR and with an enzyme activity assay. For the trans-cyanohydrin reaction (transcyanation) a two step reaction could be established. The results furthermore indicate a fast deactivation of the enzyme at low pH and a strong substrate dependence of its stability. They rule out an enzyme-HCN complex or a covalently bound carbonyl compound. Therefore the earlier postulated reaction intermediate as well as the proposed action of the catalytic triad have to be reevaluated. The calculated molecular mass could be confirmed by mass spectroscopy.
Kluyver Laboratory for Biotechnology, Delft University of Technology, Julianalaan 67, 2628 BC, Delft, The Netherlands. hanefeld@stm.tudelft.nl
U
U
Hanefeld
A J
AJ
Straathof
J J
JJ
Heijnen
D000446:Aldehyde-Lyases / Q000737:chemistry* / Q000302:isolation & purification; D001547:Benzaldehydes / Q000737:chemistry; D004789:Enzyme Activation; D004795:Enzyme Stability; D006856:Hydrogen Cyanide / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D010940:Plant Proteins / Q000737:chemistry* / Q000302:isolation & purification
D001547:Benzaldehydes; D010940:Plant Proteins; D006856:Hydrogen Cyanide; D000446:Aldehyde-Lyases; C087495:acetone-cyanohydrin lyase; C032175:benzaldehyde