Table 1.

Classification of MT-Isomers

S.No	Based on		Classification
1.	Metals Present		Major -MT-1 &MT-2
			Minor - MT-3 &MT-4
2.	Proteins are encoded by a family of genes which are located on chromosome 16q13		MT I a, MT I b, MT I c etc
3.	Biological system	Central nervous system	MT-I, MT-II and MT-III
		Neurons	MT-III
4.	Family of eukaryote and some are in prokaryote	Proteins with sequences related to mammalian MT	MT- i
		Proteins with sequences not related to mammalian MT	MT- ii
		Peptides that are not genetically encoded	MT- iii
5.	Expressed in tissues	Liver and kidney	MT-I and MT-II
		Brain and to male reproductive organs	MT-III
		Specific to stratified squamous epithelia	MT-IV