How does a catalyst work


An enzyme works as a catalyst because it has all those sites where the molecule can bind to. So it reduces the amount of energy needed. But how does a metal or other molecule have these sites, when its like a ball?

In: Chemistry

A catalyst isn’t a particular thing, it’s a role a thing plays. Any chemical that promotes some other reaction is a catalyst. It’s hard to give a solid definition of how a broad class of things work.

For a chemical reaction to happen, first you need to put some energy into it to get the reaction going. This is called activation energy. You can imagine it like rolling a rock up a little hill so then it can roll down a big hill, [like this ]( This is why fuel like gas doesn’t just explode on it’s own accord; the spark gives it the necessary activation energy to start.

I like to imagine it’s like doing something you don’t want to do, like tidying up. It’s much easier to just sit and procrastinate and even though you know you need to get started tidying, it’s just so hard to actually get up. Enzymes, whether they’re inorganic ones like metals, or enzymes, work by providing a different reaction path, breaking the reaction into smaller stages, each one requiring a smaller activation energy.

It’s like bribing yourself with the promise of a nice cool drink from the fridge to help you to start tidying. Getting up to do chores feels like a massive task, but getting up to get the quick enjoyment of something nice, that’s *much* likelier to break you out of your procrastination stupor.

And once you’ve put your phone away and stood up, you have momentum, it’s easier to get going with work.

All chemical reactions involve the transfer of electrons. Enzymes seem way more complicated than metallic catalysts, but they’re not, they just help provide an alternative route for electrons to bounce around. The big complexity of enzymes is mostly due to fine tuning for their specific biological environment they need to function in.

Phyllis must assemble a finished product by taking part A and joining it with part B. It’s very fiddly. The parts are hard to join up.

Michael comes along. He’s able to make the product by first disassembling A which makes it much easier to fit onto B. It’s much faster.

Michael is the catalyst.

We usually write the equation as just the uncatalysed version: A + B = C

But the catalyst actually puts in other steps.

A + Y = X

X + B = C

But we tend to ignore those middle steps because the result is what we’re interested in. (X would be a compound including the catalyst, which is then left over again when C is made).