metallothionein

[mĭ-tăl′ō-thī′ə-nēĭn]
n.
  1. A small metal-binding protein, rich in sulfur-containing amino acids, that is synthesized in the liver and kidney and important in ion transport.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.