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Is it odd to have a favorite protein?
Well…I don’t think so.
Probably because my favorite protein happens to remind me of one of my favorite childhood
games.
Pac-Man.
If you haven’t played Pac-Man before then chances are…we are much, much older than
you.
But now you can play it on Google- just Google Pac-Man—it’s a Google Doodle!
Anyway, I digress.
See in Pac-Man, you have this little character.
It goes around, finds these pebbles, and the pebbles fit right into it.
Well a lot of illustrations that you will find of enzymes happen to look, to us, a lot
like Pac-Man.
I remember P for pac-man and p for protein.
Most enzymes are proteins.
In the game we mentioned these little pebbles that Pac-Man goes after.
Well enzymes have a specifically shaped area, called an active site, where items can bind,
called substrates.
It’s very specific binding because the active site is specifically shaped for the substrate
that binds there.
Very specific.
So what happens when substrates bind an enzyme?
Well usually the substrate is held there with weak bonds because it’s not going to stay
there forever.
Something called induced fit will happen which means the active site can change its shape
even more to bind that substrate perfectly.
Like…an enzyme-substrate hug.
The enzyme can either build up or break down the substrates that specifically bind to it,
and we call the resulting item the product.
An enzyme has the ability to really speed up reactions.
Reactions that technically could happen on their own …but with the help of enzymes,
they can be sped up to make processes effective for life.
Let me give you a great real life example.
The enzyme lactase.
Another really cool thing about enzymes is that they often end in -ase like lactase.
Many sugars, on the other hand, end in -ose and lactose is an example of a sugar.
Lactose is a disaccharide meaning it contains two sugar molecules bound together.
We don’t actually digest it so well in that form.
It’s big.
The enzyme lactase has the ability to break lactose into smaller parts that our body can
digest, and this is a lot better option than waiting for a chemical reaction with lactose
to happen spontaneously.
With lactase enzyme, lactose can be broken down quickly and digested.
Now there are some people that do not produce enough lactase enzymes.
They can be what we call lactose intolerant which means that consuming foods that have
lactose, milk sugar, in them can make them sick.
They can’t break the lactose down efficiently without lactase enzymes.
Now in that example, one thing to point out---lactase, the enzyme, can break down a lot of lactose,
the substrate.
The lactase doesn’t get used up in the reaction.
It’s still there.
We call enzymes a catalyst because they can be used over and over in the reaction.
By the way, your digestive system uses all kinds of enzymes.
You have lipase that breaks down lipids- which are fats.
You have amylase which breaks down starch.
You have protease which breaks down proteins.
So as you can see, the digestive system is very involved with enzymes.
Another thing to point out is that enzymes don’t always work alone.
Sometimes they get some help.
Some often underappreciated but essential little helpers are called cofactors and coenzymes.
They may bind to the substrate or to the active site.
They help the enzyme do its job of building up or breaking down substrates into products.
Now you didn’t forget our Pac-Man analogy yet right?
In the game Pac-Man, there are these ghosts.
And when they touch Pac-Man, it makes this sound…it’s like…ner ner ner ner.
The Pac-Man’s shape gets all distorted in the process.
So what does this have to do with enzymes?
No, there aren’t ghosts around.
But enzymes do have certain ideal conditions that they like.
For example, an enzyme that is in your stomach would have an ideal pH that is very acidic
because the environment in your stomach is very acidic.
Different enzymes have different ideal pH and temperature ranges.
If an environment changes out of an enzyme’s ideal pH or temperature range, then something
that reminds me a lot of that horrible sound I tried to make can happen.
The enzyme becomes…denatured!
That means its shape becomes distorted- it can no longer bind to its substrate.
It can no longer work correctly.
It is…finished.
Well….that’s a dramatic end to enzymes.
Keep in mind that if you have an interest in this topic, many medical researchers have
a large focus on enzymes.
Enzymes regulate a lot of body processes, and many diseases can involve specific enzyme
production…or the lack of it.
Well that’s it for the Amoeba Sisters and we remind you to stay curious!