Final answer:
Sigmoid kinetics in enzymatic reactions is caused by a phenomenon known as Michaelis-Menten kinetics. Regulatory enzymes exhibit sigmoid kinetics, while non-regulatory enzymes show hyperbolic kinetics.
Step-by-step explanation:
The phenomenon that causes sigmoid kinetics is commonly seen in enzymatic reactions. This type of kinetics is known as Michaelis-Menten kinetics, named after the biochemists who discovered it. The curve describing sigmoid kinetics is often referred to as a rectangular hyperbola.
Michaelis and Menten derived a rate equation consistent with sigmoid kinetics by making several assumptions about the behavior of the enzyme (E), substrate (S), and product (P) in a catalyzed reaction. This equation is commonly used to describe the velocity of enzymes.
It is important to note that regulatory enzymes tend to exhibit sigmoid kinetics, while non-regulatory enzymes show hyperbolic kinetics.