© Khopkins2010, Wikimedia CommonsA negative differential response occurs in substrate inhibition, a process that occurs in about 20% of all known enzymes.
Ever since the late 19th century, physicists have known about a counterintuitive property of some electric circuits called negative resistance. Typically, increasing the voltage in a circuit causes the electric current to increase as well.
But under some conditions, increasing the voltage can cause the current to decrease instead. This basically means that pushing harder on the electric charges actually slows them down.
Due to the relationship between current, voltage, and resistance, in these situations
the resistance produces power rather than consuming it, resulting in a "negative resistance." Today, negative resistance devices have a wide variety of applications, such as in fluorescent lights and Gunn diodes, which are used in radar guns and automatic door openers, among other devices.
Most known examples of negative resistance occur in human-engineered devices rather than in nature. However, in a new study published in the
New Journal of Physics, Gianmaria Falasco and coauthors from the University of Luxembourg have shown that an analogous property called negative differential response is actually a widespread phenomenon that is
found in many biochemical reactions that occur in living organisms. They identify the property in several vital biochemical processes, such as
enzyme activity, DNA replication, and ATP production.
It seems that nature has used this property to optimize these processes and make living things operate more efficiently at the molecular scale.
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