Purification of a Plasmodium berghei neutral endopeptidase and its localization in merozoite.

A Plasmodium berghei neutral endopeptidase specific for the fluorogenic substrates valyl-leucyl-glycyl-arginyl/lysyl-aminoethyl-carbazole was purified by Fast Protein Liquid Chromatography. The enzyme was a Mr 68,000 polypeptide. Immunization of mice with the purified enzyme gave a specific antiserum, as demonstrated by immunoblotting. Immunofluorescence with this antiserum showed a strong labelling of P. berghei merozoites in mature segmented schizonts and of merozoites released from schizont-infected red blood cell. This labelling was mainly associated with the merozoite apex. It is possible that this endopeptidase is involved in the reinvasion.