The state of ferriprotoporphyrin IX in malaria pigment.

This is the authors' abstract. We don't add key points for this paper.

To evaluate the state of ferriprotoporphyrin IX (FP) in malaria pigment, mouse erythrocytes infected with Plasmodium berghei NYU-2 parasites were lysed by hypotonic shock, and hemoglobin and other soluble material were removed by extensive washing. The amount of FP recovered in the insoluble pellet was 2.1 mumol/ml of packed infected erythrocytes, of which approximately 1% was attributable to hemoglobin contamination. This crude preparation then was digested with a nonspecific protease from Streptomyces griseus and extracted with chloroform/methanol. The residue of insoluble dark brown material had the spectral and solubility properties characteristic of the FP of malaria pigment, and various different preparations contained from 82 to 99% of FP by weight. By elemental analysis, highly purified preparations contained no chlorine and had an oxygen content consistent with 1 mol of hydroxyl/mol of FP (oxygen content: calculated, 12.6%; found, 12.5%). In comparison to hematin purchased from Sigma, which had a measured oxygen content of 14.7%, the low oxygen form of hematin purified from malaria pigment was remarkably less soluble in ethanol, 3% sodium bicarbonate, and chloroform.