Studies on the metabolism of rat liver copper-metallothionein.
The degradation of purified 35S-labelled rat liver isometallothioneins (MT) by lysosomal extracts was studied. Zn-MT-I was more readily hydrolysed than Zn-MT-II, but no significant degradation of the Cu-containing metallothioneins could be detected, even after 24 h incubation. The susceptibility of MT to degradation in vitro may be related to the strength of the metal-thiolate bonds. However, the turnover rates of cytosolic MT in vivo, as established by pulse-labelling techniques, are apparently subject to different controls. The half-lives of MT-I and -II in the liver cytosol of Cu2+-injected rats were only 15.4 +/- 1.5 and 18.2 +/- 1.1 h respectively. Approx. 25% of the total liver MT was present in particulate fractions (probably in lysosomes) of the liver and had a half-life of 25.1 +/- 4.1 h.
D000818:Animals; D002850:Chromatography, Gel; D003300:Copper / Q000378:metabolism; D003545:Cysteine / Q000378:metabolism; D006207:Half-Life; D066298:In Vitro Techniques; D008099:Liver / Q000378:metabolism*; D008297:Male; D008668:Metallothionein / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D013347:Subcellular Fractions / Q000378:metabolism
C007121:copper thionein; C021267:zinc thionein; D003300:Copper; D008668:Metallothionein; D003545:Cysteine