Key response

Key reactions occur mainly in more complex metabolic pathways and are an important control instrument there.

Key reactions / key enzymes

If you look at the entire metabolic path from the starting material to the finished product , a whole series of enzymes is used on the way there . Not all enzymes are regulated for control purposes, only certain ones. The regulated enzymes usually catalyze a strongly exergonic reaction that is not reversible under conditions such as those found in cells. This reaction step is the key reaction. The enzyme that catalyzes this reaction is also known as the key enzyme.

Pacemaker reactions / pacemaker enzymes

The regulated enzymes in a metabolic chain work relatively slowly. They are therefore important control points for the metabolic pathway. If there are several key reactions in a metabolic pathway, the slowest reaction (which thus determines the speed) is called the pacemaker reaction. The enzyme that catalyzes this reaction is also known as the pacemaker enzyme.

Individual evidence

• Florian Horn: Human Biochemistry , Thieme, 2009, ISBN 978-3-13-130884-9