Purification of metallothionein from thymus and spleen,induced by zinc administration

Zinc is an essential trace element to maintain human and generally mammal homeostasis; its biological signification could be explained through the participation or as structural element of more than 200 protein molecules in mammals.

The synthesis of proteins in spleen and thymus of rats is induced by zinc, a fact which moved us to purify and isolate such proteins, before proceeding to its identification or characterization. Rats are treated with zinc during 4 weeks and then sacrificed; blood is extracted under light ether anesthesia. The extracts of thymus and spleen were prepared by homogenization with Tris‐HC1 buffer 1.0 × 10^‐2M pH 7.4 and submitted to Sephadex G‐75 column (40 × 1.6 cm) after centrifugation and filtration through 0.45 μ filters. The elution profile of proteins were established at 253 and 280 nm, and zinc concentration was measured by atomic absorption spectrophotometry. The peak containing zinc was submitted to a second column of Sephadex G‐25 (40×1.6 cm) obtaining a peak of purified protein with physico‐chemical characteristics similar to metallothionein.