Abstract
Calcineurin (CN) is a Ca2+/calmodulin-dependent protein serine/threonine phosphatase that plays a pivotal role in a variety of cellular functions, such as the nerve and immune systems in our body. It has been shown that CN can be stimulated by divalent ions, such as Mn2+ and Ni2+, and inhibited by Zn2+. In this study, when we tested the effects of a chemical compound on some enzyme activities, we happened to find that elutants form the O-ring of a plastic tube used for the storage of the chemical compound specifically inhibits CN activity in vitro. We tried to elute the inhibitors with several solvents, partially purified the inhibitors, which were hydrophilic and hydrophobic ones, and found that one of the CN inhibitors could be Zn2+. Although the hydrophobic inhibitor(s) of CN eluted with ethanol have not been identified, the inhibitors were not plasticizers, such as potassium hydrogen phthalate and diethyl phthalate. Moreover, we found that some ordinary plastic and rubber products contain CN inhibitor(s). These results indicate that CN inhibitors eluted from ordinary plastic goods may disturb reliability and fidelity of our experimental data and/or be toxic to our body by disturbing our nerve and immune systems.
