This family consists of Pirin proteins from both eukaryotes andprokaryotes. The function of Pirin is unknown but the genecoding for this protein is known to be expressed in all tissuesin the human body although it is expressed most strongly in theliver and heart. Pirin is known to be a nuclear protein,exclusively localised within the nucleoplasma and predominantlyconcentrated within dot-like subnuclear structures [1]. A tomatohomologue of human Pirin has been found to be induced duringprogrammed cell death [2]. Human Pirin interacts with Bcl-3 andNFI [3] and hence is probably involved in the regulation of DNAtranscription and replication. It appears to be anFe(II)-containing member of the Cupin superfamily.