A Note on Haemerythrin

Abstract

1. The effect of change of temperature on the dissociation curve of oxyhaemerythrin is shown. The heat of combination between haemerythrin and oxygen has been calculated to be 10,350 calories per gramme molecule of oxygen. 2. It has been shown that oxyhaemerythrin is only stable over a small range of pH. The pigment appears to be most stable at pH 8.0 and 9.0. Variation of hydrogen-ion concentration between pH 6.0 and pH 10.0 appears to have little effect on the dissociation curve of oxyhaemerythrin. 3. Oxyhaemerythrin can be converted to a yellow "methaemerythrin" by the action of oxidising agents. The change occurs spontaneously at slightly acid hydrogen-ion concentrations. 4. Attempts to show the presence of haem in the haemerythrin molecule have been unsuccessful. 5. The nature of the purple colour produced by the action of concentrated H2SO4 on a solution of oxyhaemerythrin is discussed. 6. Photographs of the absorption spectra of oxyhaemerythrin, methaemerythrin and the H2SO4 product of oxyhaemerythrin are shown.