What is true about enzyme functions?

Enzymes are proteins that help speed up metabolism, or the chemical reactions in our bodies. They build some substances and break others down. All living things have enzymes.

Table of Contents Show

What do enzymes do?
What are the different types of enzymes?
Parts of Enzymes
What are the parts of an enzyme?
How do temperature and pH affect enzymes?
Common Conditions & Disorders
What health conditions can enzyme problems cause?
How are enzyme tests used to diagnose health conditions?
Caring for Your Enzymes
Do I need to take enzyme supplements?
Can medications affect enzyme levels?
When to Call a Doctor

Our bodies naturally produce enzymes. But enzymes are also in manufactured products and food.

What do enzymes do?

One of the most important roles of enzymes is to aid in digestion. Digestion is the process of turning the food we eat into energy. For example, there are enzymes in our saliva, pancreas, intestines and stomach. They break down fats, proteins and carbohydrates. Enzymes use these nutrients for growth and cell repair.

Enzymes also help with:

Breathing.
Building muscle.
Nerve function.
Ridding our bodies of toxins.

What are the different types of enzymes?

There are thousands of individual enzymes in the body. Each type of enzyme only has one job. For example, the enzyme sucrase breaks down a sugar called sucrose. Lactase breaks down lactose, a kind of sugar found in milk products.

Some of the most common digestive enzymes are:

Carbohydrase breaks down carbohydrates into sugars.
Lipase breaks down fats into fatty acids.
Protease breaks down protein into amino acids.

Parts of Enzymes

What are the parts of an enzyme?

Each enzyme has an “active site.” This area has a unique shape. The substance an enzyme works on is a substrate. The substrate also has a unique shape. The enzyme and the substrate must fit together to work.

How do temperature and pH affect enzymes?

Enzymes need the right conditions to work. If conditions aren’t right, enzymes can change shape. Then, they no longer fit with substrates, so they don’t work correctly.

Each enzyme has an ideal temperature and pH:

pH: Enzymes are sensitive to acidity and alkalinity. They don’t work properly if an environment is too acidic or basic. For example, an enzyme in the stomach called pepsin breaks down proteins. If your stomach doesn’t have enough acid, pepsin can’t function optimally.
Temperature: Enzymes work best when your body temperature is normal, about 98.6°F (37°C). As temperature increases, enzyme reactions increase. But if the temperature gets too high, the enzyme stops working. That’s why a high fever can disrupt bodily functions.

Common Conditions & Disorders

What health conditions can enzyme problems cause?

Metabolic disorders are often the result of not having enough of a certain enzyme. Parents can pass them to their children through genes (inherited). Some examples of inherited metabolic disorders include:

Fabry disease prevents body from making enzymes (alpha-galactosidase A) that break down fat (lipids).
Krabbe disease (globoid cell leukodystrophy) affects enzymes needed for the protective covering (myelin) on nerve cells (Central Nervous System).
Maple syrup urine disease affects enzymes needed to break down certain branch chain amino acids.

Other health conditions related to enzyme imbalances include:

How are enzyme tests used to diagnose health conditions?

Your healthcare provider can use a variety of enzyme and protein blood tests to check for certain health conditions. For example, elevated liver enzymes could be a sign of liver disease.

Caring for Your Enzymes

Do I need to take enzyme supplements?

People without chronic health conditions can usually get the enzymes they need from a healthy diet. But, if you have certain health conditions, your healthcare provider may recommend taking enzyme supplements. For instance, many people with EPI may take a digestive enzyme before they eat. This helps their bodies absorb nutrients from food. Talk to your healthcare provider before taking any type of enzyme supplement.

Can medications affect enzyme levels?

Some medications affect enzyme levels. For example, antibiotics can kill certain bacteria needed for some enzymes to work their best. This is the reason antibiotics may cause diarrhea. To kill the bacteria making you sick, they also wipe out important good bacteria that aid in digestion.

Statins (medications that lower cholesterol) can raise liver enzymes and muscle enzymes. They may increase the risk of damage to the liver or muscles.

When to Call a Doctor

You won’t know if you have an enzyme problem without a blood test. Contact your doctor if you experience any of the following problems:

A note from Cleveland Clinic

Enzymes help facilitate biochemical reactions in our bodies. They aid in everything from breathing to digestion. Having too little or too much of a certain enzyme can lead to health problems. Some people with chronic conditions may need to take enzyme supplements to help their bodies work as they should. Only take enzyme supplements under the supervision of your healthcare provider.

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Page ID6433

Enzyme Function
Summary
Explore More
1. Explore More I
2. Explore More II
Review

Do cells have one enzyme with lots of functions, or many enzymes, each with just one function?

Enzymes. Magical proteins necessary for life. So how do enzymes work? How do they catalyze just one specific biochemical reaction? In a puzzle, only two pieces will fit together properly. Understanding that is one of the main steps in understanding how enzymes work.

How do enzymes speed up biochemical reactions so dramatically? Like all catalysts, enzymes work by lowering the activation energy of chemical reactions. Activation energy is the energy needed to start a chemical reaction. This is illustrated in Figure below. The biochemical reaction shown in the figure requires about three times as much activation energy without the enzyme as it does with the enzyme.

An animation of how enzymes work can be seen at http://www.youtube.com/watch?v=CZD5xsOKres (2:02).

As you view Enzyme Animation, focus on this concept:

The reaction represented by this graph is a combustion reaction involving the reactants glucose (C6H12O6) and oxygen (O2). The products of the reaction are carbon dioxide (CO2) and water (H2O). Energy is also released during the reaction. The enzyme speeds up the reaction by lowering the activation energy needed for the reaction to start. Compare the activation energy with and without the enzyme.

Enzymes generally lower activation energy by reducing the energy needed for reactants to come together and react. For example:

Enzymes bring reactants together so they don’t have to expend energy moving about until they collide at random. Enzymes bind both reactant molecules (called the substrate), tightly and specifically, at a site on the enzyme molecule called the active site (Figurebelow).
By binding reactants at the active site, enzymes also position reactants correctly, so they do not have to overcome intermolecular forces that would otherwise push them apart. This allows the molecules to interact with less energy.
Enzymes may also allow reactions to occur by different pathways that have lower activation energy.

The active site is specific for the reactants of the biochemical reaction the enzyme catalyzes. Similar to puzzle pieces fitting together, the active site can only bind certain substrates.

This enzyme molecule binds reactant molecules—called substrate—at its active site, forming an enzyme-substrate complex. This brings the reactants together and positions them correctly so the reaction can occur. After the reaction, the products are released from the enzyme’s active site. This frees up the enzyme so it can catalyze additional reactions.

The activities of enzymes also depend on the temperature, ionic conditions, and the pH of the surroundings. Some enzymes work best at acidic pHs, while others work best in neutral environments.

Digestive enzymes secreted in the acidic environment (low pH) of the stomach help break down proteins into smaller molecules. The main digestive enzyme in the stomach is pepsin, which works best at a pH of about 1.5. These enzymes would not work optimally at other pHs. Trypsin is another enzyme in the digestive system, which breaks protein chains in food into smaller parts. Trypsin works in the small intestine, which is not an acidic environment. Trypsin's optimum pH is about 8.
Biochemical reactions are optimal at physiological temperatures. For example, mostbiochemical reactions work best at the normal body temperature of 98.6˚F. Many enzymes lose function at lower and higher temperatures. At higher temperatures, an enzyme’s shape deteriorates. Only when the temperature comes back to normal does the enzyme regain its shape and normal activity.

Enzymes work by lowering the activation energy needed to start biochemical reactions.
The activities of enzymes depend on the temperature, ionic conditions, and the pH of the surroundings.

How do enzymes speed up biochemical reactions?
Where is the active site located? Explain the role of the active site?
Complete this sentence: The activities of enzymes depends on the __________, __________ conditions, and the __________ of the surroundings.
Distinguish between the conditions needed for the proper functioning of pepsin and trypsin.

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