Atomic absorption studies indicate that the DNA-dependent RNA polymerase II from wheat germ contains about 7 tightly bound zinc atoms per enzyme molecule. This value has been repeatedly obtained with a number of enzyme preparations subjected to varying conditions of purification and dialysis. However, prolonged dialysis of the enzyme with the metal chelator o-phenanthroline results in the loss of enzyme activity and extraction of the bound zinc. Other metals including copper, cobalt, manganese, magnesium, chromium, nickel and iron were not present in significant amounts. © 1977.
Petranyl, P., Jendrisak, J. J., & Burgess, R. R. (1977). RNA polymerase II from wheat germ contains tightly bound zinc. Biochemical and Biophysical Research Communications, 74(3), 1031–1038. https://doi.org/10.1016/0006-291X(77)91621-7