Calcineurin is a heterodimeric phosphatase protein, also known as calcium-dependent serine-threonine phosphatase. The structure consists of a catalytic subunit alpha, Calcineurin A (57-59KDa) the active site and a Ca2+ binding unit, Calcineurin B (19-20KDa) the regulatory subunit(1). Calcineurin plays a key role in the T-cell response growth and differentiation mechanism, regulating the activation of the Nuclear factor of activated T-cells (NFATc) which are important in the expression of IL-2 genes. Calcineurin has been the target of inhibitors, the novel and structural immune-suppressants antifungal drugs(2). Genetic studies in yeast and fungi established the molecular basis of the inhibition mechanism by cyclosporine A and FK506 (3).