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Kuliah II - Digestive Enzymes

Enzymes are protein molecules that catalyze chemical reactions and are essential for digestion. Digestive enzymes are produced in various organs like the salivary glands, stomach, pancreas, and small intestine. These enzymes break down large food molecules like carbohydrates, proteins, and fats into smaller molecules that can be absorbed by the body. For example, the enzyme amylase breaks down starch into maltose in the mouth and small intestine, while proteases like pepsin and trypsin digest proteins in the stomach and pancreas. Without these digestive enzymes, animals would not be able to break down food quickly enough to get the nutrients and energy needed for survival.

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26 views22 pages

Kuliah II - Digestive Enzymes

Enzymes are protein molecules that catalyze chemical reactions and are essential for digestion. Digestive enzymes are produced in various organs like the salivary glands, stomach, pancreas, and small intestine. These enzymes break down large food molecules like carbohydrates, proteins, and fats into smaller molecules that can be absorbed by the body. For example, the enzyme amylase breaks down starch into maltose in the mouth and small intestine, while proteases like pepsin and trypsin digest proteins in the stomach and pancreas. Without these digestive enzymes, animals would not be able to break down food quickly enough to get the nutrients and energy needed for survival.

Uploaded by

Hastomo Nur Hidayatulloh
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
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Download as PDF, TXT or read online on Scribd
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Enzymes

Pengertian enzim
• Enzymes are globular proteins that control biological
reactions.

• Digestive enzymes speed up the breakdown


(hydrolysis) of food molecules into their ‘building
block’ components.

• These reactions occur outside of the cells lining the


gut.
Contoh enzim sucrase

•Sucrose binds to the active site on sucrase,


and this puts stress on the bond between
the 2 sugars that make up sucrose.

•The bond breaks, releasing glucose and


fructose.
Mekanisme kerja enzim
Naming and classification of enzymes

• There are 2 systems used for naming enzymes:

1. The suffix ‘-ase’ is used with the root name of


the substance being acted upon,

• for example, when sucrose (sugar) is digested, it is


acted upon by an enzyme called sucrase.
Naming and classification of enzymes

2. The type of chemical reaction involved as the enzyme


functions,

• for example, when sucrase acts on sucrose, it breaks it into a molecule of


glucose and a molecule of fructose.

• This reaction involves adding a water molecule to break a chemical bond


and so the enzyme is a hydrolase.

• All digestive enzymes belong to this hydrolase class.


• whereas most of the enzymes involved in
energy release for muscular contraction are
oxidation-reduction enzymes such

•as oxidases, hydrogenases and


dehydrogenases.
Chemical structure of enzymes

• Enzymes are large protein molecules, all of


which have their own specific 3D shape.

• Embedded within the shape is a region known as


the ‘active site’, which can attract other suitably
shaped molecules to bind to the site.
•The analogy that is often used to describe
this mechanism is that of a key fitting into a
lock.

•The enzyme serves as the lock and the


attracted molecule (called the substrate) is
the key.
•Once the chemical reaction within this lock
and key arrangement has been completed,

•the products are released and the enzyme is


free to attract another substrate molecule.
• The rate of reaction for such a process is thousands of substrate
molecules per minute.

• If a solution of sugar is left in a sealed container, it breaks down


into glucose and fructose extremely slowly.

• In the presence of a small amount of the enzyme sucrase, the rate


of breakdown is millions of times faster.
Digestive enzymes
About digestive enzymes

•Enzymes do the work in animals, and in


their cells, to make things and break things.

• Digestive enzymes are proteins that cut


food into tiny pieces so that the body can
absorb the nutrients.
There are three main types of digestive
enzymes
•proteases,

•amylases,

•lipases.
Examples of digestive enzymes are:
•Amylase, produced in the mouth.

• break down large starch molecules into


smaller sugar molecules.

•Pepsin, produced in the stomach. ...


Examples of digestive enzymes are:

• Trypsin, produced in the pancreas. ...

• Pancreatic lipase, produced in the pancreas. ...

• Deoxyribonuclease and ribonuclease, produced


in the pancreas.
Why do animals need enzymes?

• Digestive enzymes

• speed up reactions that break down

• large molecules of carbohydrates, proteins, and fats into smaller


molecules the body can use.

• Without digestive enzymes, animals would not be able to


break down food molecules quickly enough to provide the
energy and nutrients they need to survive.
The main enzyme-producing structures of the human
digestive system are

• the salivary glands,


• stomach,
• pancreas,
• liver and
• small intestine.
Digestive juices Substance
Product formed
and enzymes digested
Saliva
Starch Maltose
Amylase
Gastric juice
Protease (pepsin) Partly digested
Proteins
and hydrochloric proteins
acid
Peptides and
Pancreatic juice Proteins
amino acids
Proteases (trypsin) Fats emulsified by
Fatty acids and
Lipases bile
glycerol
Amylase Starch
Maltose
Amino acids
Intestinal enzymes
Peptides Glucose and
Peptidases
Sucrose (sugar) fructose
Sucrase
Lactose (milk sugar) Glucose and
Lactase
Maltose galactose
Maltase
Glucose
Bile from the liver
Fats globules Fat droplets
Bile salts

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