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Identification and measurement of multimeric forms of metallothionein in mouse tissues utilizing the Ames dwarf model of delayed aging
Author(s) -
Swinscoe John C.,
Meyer Mandy M.,
BrownBorg Holly M.,
Carlson Edward C.
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.5.a1086-b
Subject(s) - metallothionein , oxidative stress , western blot , cysteine , gene isoform , kidney , biochemistry , chemistry , microbiology and biotechnology , biology , oxidative phosphorylation , antioxidant , genetics , gene , enzyme
Metallothionein 1 and 2 (MT) are the most widely distributed and abundant of the four known vertebrate MT isoforms. These small proteins (61–63 amino‐acids) are metal‐ binding thiols (20 cysteine residues) and likely serve as metal detoxifying agents that assist in redox pathways and free radical scavenging. In solutions similar to the internal millieu, monomeric MT readily forms homo‐ and/or heterodimers and multimers via oxidative cystine bridges and metal‐bridged clusters. Therefore, monomeric MT probably does not accumulate intracellularly. Evidence suggests that the long‐lived Ames dwarf mouse has an elevated antioxidant defense capability that may lower oxidative stress. We speculate that MT levels might also be elevated in these tissues and here report a two‐fold increase of multimeric MT protein in dwarf heart, liver and kidney, compared to controls, using a competitive ELISA assay. The ELISA was modified in order to estimate the percent of the total MT that is oxidized and our data indicate that in control animals it is 10–16% and 0% in dwarfs. In addition, our comparative Western blot data for dwarf and control mice show that in heart, liver and kidney, multimeric forms of MT within the same tissue are similar, but are disparate between different tissues. The apparent absence of oxidized MT in the dwarf tissues may indicate a reduction in the level of oxidative stress in these mice, and the biological importance of these several multimeric forms of MT awaits further study.