Similarities between metallothionein and low molecular weight testicular cadmium-binding protein

The incorporation of 35S-cysteine and 3H-glutamic acid was studied in mouse hepatic and renal metallothionein and in testicular cadmium-binding protein of similar molecular weight. Preferential incorporation of 35S-cysteine over 3H-glutamic acid was observed not only in hepatic and renal metallothionein, but also in testicular cadmium-binding protein. When the antigenic reactivity of these proteins was compared, all three proteins reacted with the metallothionein antibody. These similarities suggest that the low molecular weight testicular cadmium-binding protein is apparently metallothionein.