Figure 10.

The result of blending first and zero-order responses in a double cycle. High Kms (Michaelis constant) result in pure first-order ultrasensitivity. As the Kms are reduced, more zero-order sensitivity is blended into the first-order ultrasensitive response. Zero-order ultrasensitivity gives a spike at higher saturation. The blending of the two effects allows a wider range of signal over which we can achieve higher sensitivity.