Enzyme Examples, Cofactors/Coenzymes, Inhibitors, and Feedback Inhibition

Summary

The video script delves into the fascinating world of enzymes, exploring their crucial role in biological processes. It introduces various enzymes involved in human digestion, such as amylase, lipase, pepsin, trypsin, and nucleases, and their specific functions. The script also explains the importance of cofactors and coenzymes in enzyme activity and discusses enzyme inhibitors, including competitive and noncompetitive types, and their applications in feedback inhibition. The significance of understanding enzymes is highlighted through their relevance in medicine, exemplified by ACE inhibitors for high blood pressure and antibiotics like penicillin that target bacterial enzymes.

Takeaways

• 🦕 Enzymes can become fascinating subjects of interest, with people developing favorites like favorite dinosaurs or flowers, but for enzymes, it's ATP synthase for the speaker.
• 🌟 The video script delves deeper into enzymes, discussing enzyme examples, cofactors and coenzymes, inhibitors, and feedback inhibition.
• 🔍 Enzyme examples are crucial to understand their importance in living organisms, especially in human digestion where they break down carbohydrates, lipids, proteins, and nucleic acids.
• 🦷 Amylase, lipase, pepsin, trypsin, and nucleases are specific enzymes in the human body that break down different biomolecules during digestion.
• 🌿 Enzymes are not exclusive to humans; they are found in all living organisms, including plants like the venus flytrap and even in viruses.
• 🔗 Cofactors and coenzymes are essential for the function of many enzymes, with cofactors often being inorganic and coenzymes organic, like certain vitamins.
• 🔒 Inhibitors can either be reversible or irreversible, and they can be competitive, blocking the active site, or noncompetitive, binding elsewhere on the enzyme and causing a conformational change.
• 🚫 Inhibitors are not always harmful; they are used by the body for processes like feedback inhibition, which helps regulate biological pathways.
• 💊 Medications often work by inhibiting enzymes, such as ACE inhibitors used for high blood pressure, which block the production of angiotensin II.
• 🛡 Penicillin, an antibiotic, works by inhibiting the enzyme transpeptidase, preventing bacteria from building their cell walls.
• 🧬 Understanding enzymes is significant for grasping biological processes and for the development and action of many medications.

Q & A

What is the significance of discovering favorites in the context of learning about science topics?

Discovering favorites in science, such as a favorite dinosaur or enzyme, helps to deepen interest and engagement with the subject matter, making it more relatable and easier to understand the importance of various elements in the scientific world.

Why is ATP synthase considered the favorite enzyme by the speaker?

ATP synthase is the speaker's favorite enzyme likely due to its crucial role in cellular respiration, where it synthesizes ATP, the energy currency of the cell, making it a fascinating enzyme in terms of biological importance.

What are the four main biomolecules that enzymes in the human body focus on breaking down during digestion?

The four main biomolecules are carbohydrates, lipids, proteins, and nucleic acids, which are essential components found in food and need to be broken down for the body to utilize them.

How does amylase contribute to the digestion process?

Amylase is an enzyme that breaks down carbohydrates, specifically the glycosidic linkages in starch, into smaller carbohydrates, starting the digestion process in the mouth.

What is the role of lipase in the digestion of lipids?

Lipase breaks down lipids by cleaving the ester bonds in triglycerides, resulting in the formation of fatty acids and glycerol, which can be absorbed by the body.

What are pepsin and trypsin, and where do they act in the body?

Pepsin and trypsin are enzymes that break down proteins. Pepsin acts in the stomach, breaking proteins into peptides, while trypsin acts in the small intestine, continuing the breakdown of proteins.

How do nucleases contribute to the digestion of nucleic acids?

Nucleases break down the phosphodiester bonds in DNA and RNA, converting these nucleic acids into their building blocks, nucleotides, which can then be absorbed and utilized by the body.

What are cofactors and coenzymes, and how do they assist enzymes?

Cofactors and coenzymes are辅助分子 that help enzymes function more effectively. Cofactors are often inorganic, like zinc or iron, while coenzymes are organic, often derived from vitamins. They can be either permanent or temporary components of the enzyme, assisting in the binding and catalytic process.

What is the difference between competitive and noncompetitive inhibitors?

Competitive inhibitors compete with the substrate for binding to the enzyme's active site, while noncompetitive inhibitors bind to a different site on the enzyme, called the allosteric site, causing a conformational change that can affect the enzyme's activity.

Can you explain the concept of feedback inhibition in biological processes?

Feedback inhibition is a regulatory mechanism where the end product of a metabolic pathway inhibits an enzyme earlier in the pathway, often noncompetitively, to prevent the overproduction of the end product, thus maintaining homeostasis.

Why are enzymes important in the context of medication and disease treatment?

Enzymes are crucial for understanding and treating diseases because many medications work by targeting specific enzymes, either inhibiting or enhancing their activity, to correct imbalances or disrupt harmful processes in the body.

Outlines

00:00

🔬 Enzyme Discovery and Digestive Functions

This paragraph introduces the concept of developing favorites in scientific topics, using enzymes as an example. It highlights the speaker's favorite enzyme, ATP synthase, and sets the stage for a deeper dive into enzymes, including their examples, cofactors, coenzymes, inhibitors, and feedback inhibition. The paragraph emphasizes the importance of enzymes in digestion, describing how different enzymes like amylase, lipase, pepsin, trypsin, and nucleases break down carbohydrates, lipids, proteins, and nucleic acids respectively. It also touches on the universal presence of enzymes in all living organisms, including humans and a venus fly trap, and even viruses.

05:05

🧬 Cofactors, Inhibitors, and Biological Regulation

The second paragraph delves into the roles of cofactors and coenzymes in enzyme function, explaining their inorganic or organic nature and their importance in the enzyme-substrate interaction. It also introduces the concept of enzyme inhibitors, differentiating between reversible and irreversible inhibitors, and between competitive and noncompetitive inhibitors. The paragraph further explains the beneficial role of inhibitors in biological processes through the example of feedback inhibition in metabolic pathways. It concludes with the significance of understanding enzymes in medicine, using ACE inhibitors for high blood pressure and Penicillin as examples of how medications can target enzymes to treat diseases.

Keywords

💡Enzyme

Enzymes are biological catalysts that speed up chemical reactions in living organisms without being consumed in the process. They play a crucial role in the video's theme by illustrating their importance in various biological processes, including digestion where they break down biomolecules such as carbohydrates, lipids, proteins, and nucleic acids. The script mentions specific enzymes like amylase, lipase, pepsin, trypsin, and nucleases, each with a unique function in breaking down different types of food molecules.

💡Digestion

Digestion is the process by which the body breaks down food into nutrients that can be absorbed and used for energy, growth, and cell repair. It is central to the video's narrative as it provides examples of how enzymes, such as amylase in the mouth and lipase in the small intestine, contribute to breaking down complex food molecules into simpler forms that can be utilized by the body.

💡Biomolecules

Biomolecules refer to any of the large molecules, such as carbohydrates, lipids, proteins, and nucleic acids, that are essential to the structure and function of living cells. The script emphasizes the role of enzymes in breaking down these biomolecules during digestion, highlighting their importance in the body's ability to process and absorb nutrients.

💡Cofactors and Coenzymes

Cofactors and coenzymes are non-protein chemical compounds that are essential for the biological activity of certain enzymes. The video explains that cofactors, often inorganic like zinc or iron, and coenzymes, often organic like vitamins, assist enzymes in their catalytic activity. An example given in the script is DNA polymerase, which requires a zinc ion as a cofactor for its function in DNA replication.

💡Inhibitors

Inhibitors are molecules that decrease the activity of enzymes, and they can be reversible or irreversible. The script discusses two types of inhibitors: competitive inhibitors that compete with the substrate for the enzyme's active site, and noncompetitive inhibitors that bind to a different site on the enzyme, causing a conformational change that reduces enzyme activity. Inhibitors are relevant to the video's theme as they can be harmful, like DDT, or beneficial in controlling biological processes, such as feedback inhibition.

💡Feedback Inhibition

Feedback inhibition is a regulatory mechanism in which the end product of a metabolic pathway inhibits an enzyme involved in the pathway, thus controlling the rate of the reaction. The script provides a hypothetical example where the final product D of a metabolic pathway acts as a noncompetitive inhibitor for enzyme 1, preventing further production of D when it is already in sufficient quantities.

💡ATP Synthase

ATP synthase is an enzyme that catalyzes the synthesis of ATP (adenosine triphosphate) from ADP (adenosine diphosphate) and inorganic phosphate, using energy from a proton gradient across a membrane. The script mentions ATP synthase as the narrator's favorite enzyme, highlighting its importance in cellular energy production.

💡Protist

A protist is a eukaryotic organism that is not an animal, plant, or fungus. The script briefly mentions protists as an example of the diversity of organisms that possess enzymes, indicating the universality of enzymes across different life forms.

💡Amino Acid

Amino acids are organic compounds that are the building blocks of proteins. They contain an amino group and a carboxyl group attached to the same carbon atom, along with a side chain that varies between different amino acids. The script uses the term 'amino acid' to illustrate the complexity and specificity of enzymes, which can catalyze reactions involving these fundamental components of proteins.

💡Nitrogenous Base

Nitrogenous bases are organic compounds containing nitrogen, which are found in nucleic acids like DNA and RNA. The script refers to nitrogenous bases as part of the broader discussion on enzymes' roles in breaking down nucleic acids, contributing to the understanding of their essential functions in biological systems.

💡Transpeptidase

Transpeptidase is an enzyme that catalyzes the transfer of amino acids between peptide chains, an essential step in the synthesis of bacterial cell walls. The script mentions transpeptidase in the context of how penicillin works as an antibiotic by inhibiting this enzyme, thereby preventing bacteria from forming their cell walls and leading to their death.

Highlights

Learning about science can lead to discovering favorites in various topics, such as dinosaurs, animals, flowers, protists, amino acids, and nitrogenous bases.

The narrator expresses a personal interest in enzymes, specifically ATP synthase, and the complexity of choosing a favorite due to the vast number of fascinating enzymes.

The video aims to delve deeper into enzymes, discussing examples, cofactors and coenzymes, inhibitors, and feedback inhibition.

Enzyme examples are crucial for understanding their importance in living organisms, starting with digestion and the breakdown of carbohydrates, lipids, proteins, and nucleic acids.

Amylase is highlighted as an enzyme that breaks down starch into smaller carbohydrates, with its action taking place in the mouth.

Lipase is identified as an enzyme that breaks down lipids into fatty acids and glycerol, with its action occurring in the small intestine.

Pepsin and trypsin are enzymes that break down proteins into peptides, with pepsin acting in the stomach and trypsin in the small intestine.

Nucleases are enzymes that break down DNA and RNA into nucleotides by cleaving phosphodiester bonds.

Enzymes are not only involved in digestion but are also integral to every human body system, including the excretory, respiratory, and circulatory systems.

Enzymes are found in all living organisms, including plants like the venus fly trap, and even in viruses.

Cofactors and coenzymes are essential for enzyme function, with cofactors often being inorganic and coenzymes organic, and they can be either permanent or temporary.

DNA polymerase is given as an example of an enzyme that requires a zinc ion as a cofactor for its function in DNA replication.

Inhibitors can be reversible or irreversible and can be competitive or noncompetitive, affecting enzyme function by binding to the active site or an allosteric site.

Feedback inhibition is a biological process where the end product of a pathway can act as an inhibitor to prevent overproduction, as exemplified by a hypothetical enzyme pathway.

The significance of understanding enzymes lies in their ubiquity and critical role in biological processes, as well as their relevance to medication development for treating diseases.

ACE inhibitors, a class of blood pressure medications, work by blocking angiotensin-converting enzymes, thereby reducing blood pressure.

Penicillin, an antibiotic, inhibits the enzyme transpeptidase, preventing bacteria from building their cell walls and thus treating infections.

The video concludes by emphasizing the importance of staying curious and continuing to explore the fascinating world of enzymes.

Transcripts

Have you ever noticed how - when learning more about a science topic - we can get so interested 

that we start to discover favorites? Favorite dinosaur? I’ve found quite a few opinions there. 

Favorite animal? I’m a little obsessed. Favorite  flower? Well, sometimes a little too obvious. 

Of course, you can always get a  little more unique. Favorite protist? 

Favorite amino acid? Your favorite nitrogenous base? 

I’m a little saddened that no one has yet asked me those three above nor have they asked me 

what I’ve been waiting to be asked, and yet have often volunteered, what is your favorite enzyme? 

ATP synthase is mine, but it’s a hard choice, because there are a ton of fascinating enzymes! 

We already have an intro video about enzymes, but this video topic is about to go into 

a little more: enzyme examples, cofactors and coenzymes, inhibitors, and feedback inhibition! 

Enzyme examples are important, because without learning about some real-life examples, 

it’s kind of hard to connect to how  important they are to living things. 

Let’s start with some fascinating  enzyme examples in the human body. 

A great place to focus on: digestion. Many enzymes focus on breaking down certain biomolecules. 

You remember the four biomolecules:  carbohydrates, lipids, proteins, nucleic acids. 

These biomolecules are found in your food; you’ve got to break those biomolecules down in digestion. 

Amylase is an example of an enzyme that breaks down carbohydrates, and one action 

location is in the mouth. Amylase can break the glycosidic linkages in starch (which is 

a large carbohydrate), into smaller carbohydrates. Lipase is an example of an enzyme that breaks down 

lipids, and one action location is in the small intestine. Lipase can break the ester bonds found 

in triglycerides, which are a type of lipid, into their building blocks: fatty acids and glycerol. 

Pepsin and trypsin are some examples of enzymes that break down proteins. An action location 

for pepsin is in the stomach and an action location of trypsin is in the small intestine. 

These enzymes break the peptide bonds in proteins. Pepsin breaks proteins down into peptides. 

You even have nucleases that break down nucleic acids: that’s DNA and RNA. And yes, 

DNA and RNA can be found in your food. Nucleases break down phosphodiester bonds 

found in connected DNA and RNA and  helps break them into nucleotides. 

By the way, once all of these biomolecules are broken down into smaller pieces, there are even 

more digestive enzymes that can break them down even more. But it’s not just digestion. 

You can name any human body  system: excretory system, 

respiratory system, circulatory system:  and you’ll find there are enzymes involved. 

These enzymes might break down or build up the substances that they act upon which is needed by 

different body systems. And while you’re at it, realize that enzymes are not just for humans. 

Enzymes are found in all living organisms, like this venus fly trap here. Beyond the 

three domains of living organisms, you’ll even find some types of enzymes in viruses! 

Ok so moving on. What’s next on our list? Oh, yes, cofactors and coenzymes. So just a quick review 

from our main enzyme video: this is an enzyme here and we have our active site and a substrate that 

could fit in the active site for the enzyme to act upon. It’s an enzyme-substrate complex when 

the substrate is bonded in this active site, and there is likely induced fit where the active site 

actually changes its shape slightly for an ideal fit- an enzyme substrate hug. But the thing is 

enzymes often don’t do it all alone, and they tend to have cofactors, which tend to be inorganic like 

zinc or iron - or coenzymes, which tend to be organic like many vitamins. Cofactors 

and coenzymes may be permanent or temporary, which often depends on how they’re bonded. 

A cofactor or coenzyme may sit in this active site here. It helps the bonding of the enzyme 

and substrate so that it can work at its best and sometimes it won’t work at all without them. 

An example of a cofactor or coenzyme? You know when we’ve mentioned DNA polymerase, 

an enzyme in DNA replication? It often  has a zinc ion as a cofactor to help. 

There are also inhibitors. They might  be reversible or not reversible – a lot 

of that depends on how they bond. They  may be competitive or noncompetitive. 

Competitive inhibitors tend to sit right there in the active site, blocking a substrate from being 

able to bind. The substrates are competing with the competitive inhibitor for binding. 

Noncompetitive inhibitors bind to some other area of the enzyme, somewhere that isn’t the 

active site. This can be referred to as an  allosteric site, a site on the enzyme that 

isn’t the active site. When the noncompetitive inhibitor binds on the allosteric site, 

the enzyme has a shape change.  If the substrate still binds,  

the enzyme’s active site might  not function well. Or at all. 

You know inhibitors might sound like a bad thing. But inhibitors can be harmful or 

they can be helpful. Some examples. You might remember DDT from our biomagnification video. 

It can act as an inhibitor for certain enzymes in the human body and can cause health issues. But 

understand that our body also uses inhibitors all the time to control a lot of biological 

processes. It’s called feedback inhibition. This is a hypothetical example here but 

let’s say that enzyme 1 converts a substrate A to an intermediate B. Then enzyme 2 converts B to C. 

Then enzyme 3 converts C to a final product D. These enzymes are all working in a pathway here. 

But what if you have enough product  D now. It’s the ultimate product, 

but you have enough, and it’s wasteful to keep producing it or maybe it’s even harmful 

to make too much. Well product D might also be a noncompetitive inhibitor for enzyme 1. 

Stopping enzyme 1 from working, which will stop the process. Again, this could be reversible or 

it could be that more enzyme 1s are produced in the body if this needs to start up again. 

So to recap: we explored some real life enzyme examples, talked about cofactors and coenzymes, 

inhibitors, and feedback inhibition. But  one last thing. We’re big on asking why: 

what is the significance of learning this? 

So we know that enzymes are ubiquitous – love that word – and they are critical for understanding 

biological processes. They’re also important to understand because many of the medications 

we use to treat diseases and disorders act on enzymes. One example –high blood pressure. It can 

be harmful to your organs and blood vessels. One class of blood pressure medications is the class 

of ACE inhibitors. ACE inhibitors work by blocking angiotensin-converting enzymes. When inhibited, 

these enzymes can’t convert angiotensin to angiotensin II. Angiotensin II can be 

involved with raising blood pressure so by blocking the enzyme that helps produce it, 

it can lower blood pressure -there’s some more complexity with this to explore. By the way, 

it’s not just the human body: medications can act on enzymes in microbes that might make us sick. 

An example: Penicillin. Penicillin is an  antibiotic, but it works by inhibiting the enzyme 

transpeptidase - which prevents many types of bacteria from being able to build their cell wall. 

Well, that’s it for the Amoeba Sisters,  and we remind you to stay curious.