Zn2Mg alkaline phosphatase in an early ptolemeic mummy.

Bone samples of a ptolemeic mummy have been employed to study the mode of conservation on the intactness of Zn2Mg alkaline phosphatase in both structure and catalytic activity. A protein of M(r) = 190 +/- 10 kDa being identical to the 200 kDa enzyme of fresh human bones was successfully isolated. Regardless of age 200 kDa protein bands and a distinct subunit at 60 kDa were seen in SDS-PAGE electrophoresis. The 200 kDa band was also monitored by activity staining. The specific activity was 120 mU/mg and 65% of the respective activity obtained in the identical preparation using fresh human tibia or rib. The enzymic activity was inhibited in the presence of 1,10-phenanthroline and L-homoarginine. Radiocarbon dating supported the assignment of the mummy to the early ptolemeic period. Among the many bactericidal and fungicidal components employed for mummification were aromatic alcohols, mono- and sesquiterpenes. Pistachio resin was the major balm resin used. The microbiological sterility of the bone surface was ascertained by independent bacterial and fungal examinations.