Über Schwermetall-Inaktiviernng hochgereinigter Urease.

Abstract

For enzyme work, water redistilled from glass and reagents and glassware free from heavy metals are important. A method for determining whether water is poisonous to urease is described. The action of pro-motors, or auxo-substances, is interpreted as a protection of the enzyme against inactivation by heavy metals. Using citrate buffer (since phosphate buffer protected urease against Ag), 1 gm. atom of Ag inactivated completely about 40,000 gm. of crystalline urease. Exact figures could not be given because the Ag-urease was found to dissociate. Urea showed some ability to protect urease against Ag. Electrometric titration showed that crystalline urease can combine with more than 10 times the amount of Ag necessary for complete inactivation. Urease poisoned by Ag could be reactivated almost completely by H2S. However, 2 reactions occurred on adding Ag ions, one reversible and the other irreversible.