The Pigment (hemozoin) and Proteins of the Avian Malaria Parasite Plasmodium lophurae.*

SYNOPSIS. The use of saponin hemolysis, buffer washings and deoxyribonuclease yields quantities of erythrocyte‐free plasmodia sufficiently pure for physico‐chemical studies. The pigment produced by Plasmodium lophurae, unlike the pigments of the simian and human malarias, is of such low solubility in buffer solutions that urea is necessary as an additive to the buffer for adequate solubilization. On the basis of spectral and electrophoretic qualities, the pigment is a protein‐porphyrin complex closely resembling methemoglobin but clearly distinct from hematin. Extraction of the pigment in solvents which degrade hemoglobin, e.g. phenol, 0.1 N NaOH, cannot be used to ascertain the properties of hemozoin, for the pigment in such solvents shows a spectrum identical to hemoglobin. The soluble parasite proteins which constitute approximately 55% of the totaI volume of the parasite as revealed by electrophoretic and ultracentrifugal analysis appear to be homogeneous. They show a marked similarity to the host hemoglobin, but differ sufficiently to verify their integrity and individuality.