Correlation of metal toxicity with in vitro calmodulin inhibition.

A fundamental biochemical process that is directly and universally related to the toxicity of metals and metal compounds has yet to be identified. Results of studies reported here indicate that the toxicity of a series of divalent metal cations correlates well with the metals' ability to inhibit the Ca2+ receptor protein calmodulin (r = 0.986). Because calmodulin regulates a variety of cellular enzymes and processes including intracellular Ca2+ concentrations, calmodulin inhibition may have value for predicting metal toxicity and for revealing information about the mechanism by which metals induce toxic effects.