Zinc forms part of the active site and/or stabilizes the conformation of several enzymes. The protein metallothionein constitutes a zinc deposit from which the metal is transferred to enzymes. Zinc participates in the synthesis of nucleic acids and hence in the synthesis of proteins, principally through multi-enzyme pir 1-3 and DNA-dependent RNA polymerase, which are metallo-enzymes of zinc. Zinc is therefore necessary for normal growth, development, healing and ossification.