The present invention relates to novel protozoal cyclic GMP dependent protein kinases and genes encoding same that have been isolated from Eimeria maxima and Plasmodium falciparum. Nucleic acid molecules having sequences that encode such proteins as well as antibodies raised against such proteins are also disclosed. These enzymes may be used in screening assays to identify potential antiprotozoal agents. As well, methods to obtain such nucleic acid molecules, proteins, antibodies and inhibitor are also provided as are therapeutic compositions comprising such nucleic acid molecules, proteins, antibodies and inhibitors as well as their use to protect animals from disease caused by parasites such as Eimeria maxima and Plasmodium falciparum.