Published On: June 20, 2023

RadicalZ Q&A: How does an enzyme know what to do?

We’re back with a new blog to answer questions related to enzymes! In our other blogs, we’ve talked plenty about the power of enzymes to speed up chemical reactions, and how useful this is for industries like cosmetics and laundry. But when the time comes to add an enzyme to a chemical mix, how does it know what to do?

This is one of the top questions people search for regarding enzymes online. How do enzymes find their target molecules and make reactions happen? They might seem like tiny robots that know the exact task they have to perform, but this is not really the case. Let us delve into this issue.

The bonding process to the substrate

Let’s remind ourselves of the basics: enzymes are almost always proteins (although some are RNA molecules) that accelerate biochemical reactions. Usually, for a reaction to happen it needs a certain amount of energy to start, like a push to get all the mechanisms working. Enzymes can lower this required activation energy, facilitating the beginning of the reaction.

The molecules to which the enzymes bind are known as substrates. Each enzyme is specific for a substrate. Another point to bear in mind is that substrates do not bind to any part of the enzyme, they bind specifically to the active site, where the reaction will take place. When the binding occurs, the enzyme changes its conformation slightly and forms the enzyme/substrate complex.

How do enzymes reach the substrates with which they interact?

The specificity that makes enzymes capable of interacting with the substrate is due to their three-dimensional conformation. The final structure of the enzyme is the key factor that makes it able to bind the substrate. When the structures of the enzyme and the substrate are complementary, the structural bonds necessary for the enzyme to perform its function are produced.

But the way in which enzymes reach substrates is not indicated by any kind of internal instructions – it’s a matter of probability. Depending on how the substrates and the molecules move around in a specific environment, they will have more or less chances of encountering each other. The study of those movements falls under the scope of the fields of thermodynamics and fluid mechanics – there’s no map hidden in enzymes’ structure.

In short, enzymes do not know what to do. They are not programmed machines with instructions. Whether they bind or not is a matter of chance combined with other factors, such as the concentration of the enzyme and the substrate in the medium and the correct conformation of both.

Recently there has been a lot of research on the link between protein dynamics, solvent fluctuations and enzyme catalysis. So let’s not rule out future discoveries on how enzymes improve the binding process!

That’s all for today’s enzyme Q&A. For more, check our previous post “Can enzymes be reused?” and follow us on social media to see what questions we’ll be answering in the future!

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