Inaktivierung des Kathepsins und Papains durch Jodessigsäure und durch Halogen.

Abstract

Cathepsin or papain inactivated by iodoacetic acid recovered activity on separation either by alcohol precipitation or by dialysis, and inhibition of proteolysis by halogen acetic acids did not parallel the conversion of SH to SS in activators. The latter process took place at a relatively slow rate while inhibition was immediate. The inhibitory action of halogen acetic acids decreased with decreasing atomic weight of the halogens; if the action was mediated through selective combination of enzyme-acid compounds rather than enzyme-substrate compounds, the affinity of the various substituted acids for the prosthetic group in the enzyme might be considered to diminish with decreasing atomic weight as well. The pH of the media influenced the stability of the enzyme-halogen acetic acid compound. I and Br did not act in this way, but inhibited enzyme action partly through destruction and partly through dehydrogenation. The inactivation depended on the conc. of the halogen and the incubation time but not on the pH.