Source Year: 1998

The reasons for the deactivation of the hydroxynitrile lyase (Hnl) from rubber trees (Hevea brasiliensis) at low pH values (below 4.0), and theinfluence of buffer salts as well as the possible stabilization of the enzyme by additives were investigated. Dynamic light scattering and fluorescence spectroscopy were employed to elucidate the phenomena responsible. It was found that the Hnl tryptophan fluorescence maximum shifted to a higher wavelength and the anisotropy increased when the pH value was decreased. Furthermore, the aggregate size of the Hnl particles increased with incresing pH; therefore, an unfolding of the enzyme followed by aggregation leading to closely packed enzyme.