Metallothionein (MT) is a family of cysteine-rich, low molecular weight (MW ranging from 500 to 14000 Da) proteins. They are localized to the membrane of the Golgi apparatus. MTs have the capacity to bind both physiological (such as zinc, copper, selenium) and xenobiotic (such as cadmium, mercury, silver, arsenic) heavy metals through the thiol group of its cysteine residues, which represents nearly the 30% of its amino acidic residues.

MT was discovered in 1957 by Vallee and Margoshe from purification of a Cd-binding protein from horse (equine) renal cortex. MTs function is not clear, but experimental data suggest MTs may provide protection against metal toxicity, be involved in regulation of physiological metals (Zn and Cu) and provide protection against oxidative stress. There are four main isoforms expressed in humans (family 1, see chart below): MT1 (subtypes A, B, E, F, G, H, L, M, X), MT2, MT3, MT4. In the human body, large quantities are synthesised primarily in the liver and kidneys. Their production is dependent on availability of the dietary minerals, as zinc, copper and selenium, and the amino acids histidine and cysteine.

Read more about Metallothionein:  Structure and Classification, Yeast, Expression and Regulation

Other articles related to "metallothionein":

Zinc - Biological Role - Other Proteins
... Zinc may be held in metallothionein reserves within microorganisms or in the intestines or liver of animals ... Metallothionein in intestinal cells is capable of adjusting absorption of zinc by 15–40% ... harmful excess zinc particularly impairs copper absorption because metallothionein absorbs both metals ...
Copper Fist
... These proteins activate the transcription of the metallothionein gene in response to copper ... Metallothionein maintains copper levels in yeast ... The copper fist domain is similar in structure to metallothionein itself, and on copper binding undergoes a large conformational change, which allows DNA binding ...