Haematin Compounds

Caffeine derivatives of haematin compounds.

1. Caffeine reacts with haematin to form a caffeine-haematin compound that has a characteristic absorption spectrum. 2. Graphical analysis of the titration of haematin with caffeine shows that 2mol.prop. of caffeine split the dimeric haematin. 3. Thermodynamic parameters suggest that the reaction involves the making and breaking of hydrophobic bonds. 4. Graphical analysis shows dimeric haem to ...

Bile pigment formation in vitro from haematin and haem derivatives.

in the form of methaemoglobin, but was apparently accounted for as carboxyhaemoglobin after the addition of carbon monoxide and dithionite. 4. The green pigment is distinct from choleglobin, and its formation is not prevented by carbon monoxide, showing that oxyhaemoglobin is not an intermediate in the reaction. We wish to thank Mr B. A. Collett for technical assistance during a part of the work.

Effect of haematin on the oxidation of succinic acid by tissue preparations.

While investigating the possibility that free haematin might act as a carrier analogous to cytochrome c in the oxidation of succinate by heart muscle preparations, we found on the contrary that it had a marked inhibitory effect on the oxidation system. In order to analyze the mechanism of this inhibition we attempted to reverse it by addition of such substances as organic bases and denatured pr...

Inhibition by chlorogenic acid of haematin-catalysed retinoic acid 5,6-epoxidation.

Chlorogenic acid (3-O-caffeoylquinic acid) inhibited haematin- and haemoglobin-catalysed retinoic acid 5,6-epoxidation. Some other phenol compounds (caffeic acid and 4-hydroxy-3-methoxybenzoic acid) also showed inhibitory effects on the haematin- and haemoglobin-catalysed epoxidation, but salicylic acid did not. Of the above compounds, caffeic acid and chlorogenic acid were potent inhibitors co...

The formation of hydrogen carriers by haematin-catalyzed peroxidations; some reactions of adrenaline and adrenochrome.