Coordination of alpha-chymotrypsin and trypsin with hematin. I. Isolation and properties of hemocromes

Abstract

Alkali denatured a-chymotrypsin and trypsin react with ferriprotoporphyrin IX in alkaline media and readily forra the corresponding ferri- and ferrohaemochromes.

The affinities for protohaematin of both denatured enzymes are stronger towards the reduced forra of the pigraent. The number of haem-binding groups of the proteins appears to be higher than the histidine rests contained in their molecules.

The velocity of the reaction of combi­nation with haem increases with pH, as a previous alkali-denaturation of the pro­teins is required; at pH 7 no combination takes place.

The stabilities of the corresponding fe- rrihaemochromes of a-chymotrypsin and trypsin have been duly confirmed by zone electrophoresis carried on cellulose acetate strips.