Name: How Enzymes Work
Uploaded: 2018-11-28T09:43:15.000Z
Duration: 4 min 52 s
Description: Thousands of YouTube videos with English-Chinese subtitles! Now you can learn to understand native speakers, expand your vocabulary, and improve your pronunciation...

Every single second inside every living cell,

thousands of chemical reactions are taking place.

protein that catalyzes a chemical reaction.

makes sure the outcome is always the same.

chemical reactions used by cells to generate

The essential tasks of life such as metabolism,

protein synthesis, and cell renewal and growth

The life-sustaining power of enzymes lies in the fact

The rates of catalyzed reactions are millions to

To speed up a reaction in the absence of enzymes,

substrates are transformed into products.

the reaction, binding to its substrate and

surrounds the substrate with reactive groups

that stabilize the transition state, making

To understand how enzymes work, let's take a

Citric Acid Cycle that is catalyzed by the

It then adds the hydrogen in the hydroxyl back

Other amino acids are directly involved in catalysis.

00:02:41,040 --> 00:02:43,140
Histidine 101 acts as an acid by donating its proton.

Thanks to the chemical environment of Serine 642,

The active site of aconitase also contains

an iron-sulfur cluster that stabilizes the

position it relative to the catalytic residues.

The first step in the reaction is dehydration.

of the substrate forming the intermediate cis-aconitate.

In this step, histidine grabs a hydrogen atom

back onto the substrate.  Serine then returns its

Notice that the enzyme itself was not changed by the reaction.

and a hydrogen atom and then put them back,

for the next, so it can perform thousands

Notice also that the shape of an active site is often flexible.

Enzymes are fundamental to life on Earth,

and in every living creature on the planet.

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How Enzymes Work

essential

recognize

trigger

slightly