Abstract
The influence of various inorganic actions and anions upon activity of Aspergillus-proteinase (Takadiastase) were investigated. Of the twenty cations tested, some ions of heavy metals, especially silver and mercuric ions, were found effective to cause inactivation of the enzyme. But the addition of other metals which have been known to affect the activity of peptidases, such as cobalt, manganese, and magnesium ions, did not increase the activity of this preparation. Of the twenty anions, ferrocyan and iodic acid ions seemed to be somewhat inhibitive toward this enzyme. It was found that the enzyme inactivated by the heavy metallic ions is reactivated by either hydrogen sulfide or thiosulphate. Despite of the enzyme characteristics suffering reversible inactivation heavy metals, it is difficult to assume whether the sulfhydryl groups are essential to the activity of this fungal proteinase, since specific reagents for the sulfhydryl groups, such as ferricyanide, iodoacetate, and p-chloromercuribenzoate had no significant influence on enzyme activity.
