Stabilisation of chloroperoxidase towards peroxide dependent inactivation

The addition of polyethyleneimine with a molecular weight of 2000 to chloroperoxidase from Caldariomyces fumago dramatically improved the stability of the enzyme towards peroxide dependent inactivation. The rate constant for the H2O2-dependent inactivation of chloroperoxidase decreased from 0.0016 s(-1) to 1.1 * 10(-5) s(-1) in the presence of 1% polyethyleneimine. The stabilising effect towards tert-butyl hydroperoxide was even more impressive. The half-life of the chloroperoxidase when exposed to a solution of 40 mM tert-butyl hydroperoxide increased from 3.2 minutes to greater than or equal to 70 hours in presence of 0.1% polyethyleneimine.