sigmoidicity

sig·moid·ic·i·ty

(sig'moyd-is'i-tē),
Describing an S-shaped curve, for example, the shape of enzyme-kinetic curves for enzymes displaying positive homotropic cooperativity.
References in periodicals archive ?
50] is the drug concentration in the effect compartment yielding half of the maximal effect, and n is the sigmoidicity factor, an exponent describing the number of drug molecules that combine with each receptor molecule.
a]); and m is an exponent that signifies the sigmoidicity (shape) of the dose-effect curve, which is determined by the slope of the median-effect plot.