Occurrence and synthesis of a non-thionein, zinc-binding protein in the rainbow trout (Salmo gairdneri)

A non-thionein, Zn-binding protein (ZBP) was induced in Donaldson strain rainbow trout (Salmo gairdneri) by 7 mg/kg, i.p. injections of divalent Zn ion. The Sephacryl S-200 used for supernatant fractionation had to be saturated with Zn to recover quantitatively the Zn-ZBP complex. The ZBP was present in liver and kidney, but was absent from gill and spleen. The apparent molecular weights of the liver and kidney ZBP as estimated by gel filtration were 17,300 +/- 1300 (SD; N = 11) and 18,100 (N = 1), respectively. Starvation induced hepatic ZBP synthesis whereas cycloheximide inhibited hepatic ZBP synthesis. The quantity of hepatic ZBP synthesized varied with the temperature of the water in which the trout resided. The maximum quantity of ZBP in the liver following a single 7 mg/kg Zn injection (17 micrograms Zn/g liver wet weight) occurred at 24 hr.