Coordination of alpha-chymotrypsin and trypsin using haematin. II. Production of ferrohaemochromes by reducing action of the denatured protein on haematinic iron

Abstract

Coordination of a-Chymotrypsin and Trypsin with Haematin. — II. Production of Ferro- haemochromes by the Reducing Action of Denatured Protein on Haematinic Iron

When protohaematin reacts with alkali denatured a-chymotrypsin, trypsin or ovoalbumin, in a solution containing an excess of the protein, the progressive reduction of the ferrihaemochromes to the corresponding ferrocompounds which also takes place, can be spectrophotometrically detected by the appearance of the typical bands of the ferrohaemochromes.

The minimal Protein/Haematin molar ratio practically necessary to easily indu­ce the reduction of achymotrypsin ferrihaemochrome is about 10/1. The ferricompound of trypsin appears to be less readily reduced — this protein seems to be rather sensitive to a deep desintegration by alkali—, and even slower is the formation of the ferrohaemochrome of egg albumin — apparently rather resistant to alkali denaturation.

Those three proteins, when submitted to alkali degradation in anaerobic conditions, gradually libérate free -SH groups. The experimental fact that their ferrihaemochromes are transformed into ferrocompounds when treated by quantities of Na2S equivalent to the thiol groupings formed present in the denatured proteins,, suggest the responsability of the sulphydrils in the reductions of the ferricombinations that take place when an excess of the corresponding protein prevails.