Heterologous expression and comparative characterization of vacuolar invertases from Cu-tolerant and non-tolerant populations of Elsholtzia haichowensis

摘要: Vacuolar invertases (VINs) from Cu-tolerant and non-tolerant populations of Elsholtzia haichowensis have similar enzyme properties, the protein divergences contribute little to the varied VIN activities between contrasting populations. In our previous studies of haichowensis, vacuolar invertase (VIN) activity in roots a population was found be significantly higher than that under Cu stress. Divergences amino acid residues sucrose-binding box other regions VINs were detected. To test whether influence properties VINs, thus are relevant differences E. two genes (EhCvINV) (EhNvINV) heterologously expressed Pichia pastoris, recombinants characterized compared. Both recombinant enzymes showed temperature optima 70 °C pH 4.5–5.5. Copper as well heavy metals caused almost same inhibition EhNvINV EhCvINV. No statistically significant observed EhCvINV K m k cat values for sucrose. The results provided evidence residue had on stress not proteins. Also, some possible reasons accounting this difference discussed, such up-regulation expression gene stress, tolerance mechanisms Cu-mine plants.