STRUCTURE & FUNCTION OF ENZYME

MLT
435

ENZYME
BIOCHEMISTRY

STRUCTURE &

FUNCTION

OPT 1

HADAINA SOFIA BINTI MOHD LAZIM (2022827974)
EMYLIA ERINA BINTI ROSLAN (2022855442)
JAZREEN BINTI JAZS AZLAN (2022812562)
IZZATUL ADAWIYAH BINTI ISMAIL (2022699958)
NURUL SYAZWEEN BINTI ZULKEFLI ZARIN (2022622692)

01

1. The digestive system
Help bodybreak down larger complex molecules into smaller molecules

2. DNA Replication
Each cell in the body contain DNA
Help is replication process by unwinding the DNA coils

3. Liver enzymes
Liver break down toxin in the body
It use a range of enzyme to facilitate the process of destroying the toxins.

02

a region where a specific substrate bind to
the enzyme, catalyzing the chemical reaction.
known as "Enzyme catalytic surface".
a cleft or cavity composed of nearly 10-15
amino acid residues that help in holding the
substrate to the enzyme
possesses a specific geometrical shape and
chemical signals that allow the specific
recognition and binding between an enzyme
and a substrate

Binding site: a property of the enzyme's active site, which increase the
binding affinity of the substrate towards an enzyme



Catalytic site: a property of an enzyme's active site, which aids in the
catabolic recation of the enzyme and substrate to yield product by
reducing the activation energy

Increase the binding affinity It can change its conformation to
other mechanism include: mediate substrates' conversion
Vander Waal, hydrogen bond
and electrostatic force into product








mainly consists of non-polar
amino acid residues (no
reactivity depends on the charge/zero net charges)
environmental condition such some may consist of polar
as temperature, pH, enzyme amino acids (positive &
and substrate concentration negative charge)
reduce the activation energy to the binding must be a
further catalyze the reaction complementary pairing
between the active site and
substrate

03

APOENZYME HOLOENZYME

Definition

The catalytically inactive protein part
The catalytically active apoenzyme-

of an enzyme (incomplete enzyme)
cofactor complex (complete enzyme)

and cannot start the reaction.
and can start a reaction.

Chemical Constituents

Only made up of proteins Made up of protein and non-protein

part called as cofactors such as metal


ions, other organic molecules or

coenzymes and prosthetic groups.

Activity

Inactive of chemical reactions and
Active for chemical reactions and

they only become active after
fully capable to catalyse a

binding to a cofactor. biochemical reaction.

Cofactor

Absent proper co-factor. Present proper co-factor like metal

ions or coenzymes

Examples

DNA polymerase RNA polymerase + Sigma factor
RNA polymerase DNA polymerase + Mg2+

Pepsinogen

04

non protein molecules
assist in enzyme activity
bind to an enzyme to change its form into an active form (

holoenzyme )
2 types : organic molecules ( vitamin C)

: inorganic ions (magnesium ions)

more securely bound to
loosely bound to the

the enzyme enzyme
not affected during the
modified
enzymatic process temporarily attached
permanently attached example :

example : catalase and
transaminases and

peroxidase decarboxylases

05

Substance that bind to the active site of enzyme to initiate biological reaction to occur.



A substrate is a molecule acted upon
by an enzyme.
It will bind to the active site of
enzyme or the place that allow weak
bond to be formed between two
molecules.
When substrate binds to enzyme it
forms an enzyme-substrate
complex.
Bond that form between the
substrate and enzyme cause the;
conformational change or change the
shape of enzyme.

This will cause pressure to substrate, either forcing molecules together or tearing
them apart.
Once the reaction is complete the substrate now is called the product.
The products will become the substrate of the next reaction, until the final product
is reached.

01 LACTOSE

-Act as substrate for enzyme lactase
- Role ;Sugar produce in milk ,contains a blends of fats,
proteins and growth hormones for young mammals to
gain weight in short amount of time.

02 NUCLEIC ACID
(DNA & RNA)

-Acts as substrate for nuclease enzyme

03 FATTY ACID


-Act as substrate for lipase enzym
es
-Fats obtained from food and by the synthesis in the body

04 PROTEIN

05 -Act as substrate for enzyme peptidase
- Role in the body ; amino acid sources

STRACH

-Act as substrate for enzyme amylase
- Role in the body ; glucose source

06

1

the enzyme active site is complementary in conformation to the
substrate. The enzyme and substrate recognize each other.

Characteristics

The active site has rigid shape
Only substrate with matching shape can fit
The substrate is a key that fits the lock of active site
The older model and does not work for all enzymes

Mechanism

Active site of enzyme and substrate have complementary shapes.
Form enzyme-substrate complex.
Old bonds broken; new bonds formed.
Product has different shape from the substrate.
Product is released from enzyme.

substrate enzyme-substrate complex products
active site

enzyme

2

The enzyme change shape on binding to the substrate, so that the

conformation of substrate and enzyme active site is complementary

only after binding.

Characteristics

The active site is flexible.
The substrate and the active site of the enzyme change in

conformation until the substrate is completely bound to the enzyme.
There is greater range of substrate specificity.
The model is more accepted model than the lock and key model.

Mechanism

The active site of enzyme is not complementary to the substrate
Binding/presence of substrate
Induces slight conformational change of active site
Catalytic groups on enzyme is in correct orientation with substrate
Breaking and forming bonds
Product has different shape from the substrate
Product is released from enzyme
Enzyme returns to its original shape

substrate enzyme-substrate complex products
active site

enzyme

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REFERENCES

[Reference list APA style]
1. Berg, J. M. (2019). Biochemistry. New York: Macmillan

International Higher Education.
2. Panawala, L. (2017). What is the active site of an enzyme.

Pediaa.com.
3. Robinson, P. K. (2015). Enzymes: principles and

biotechnology. Essays in Biochemistry.
4.Abali, E.E. (2022) Lippincott Illustrated Reviews:

Biochemistry. Philadelphia: Wolters Kluwer.
5.Yokoyama, D. M. (2018, August 23). What is an Enzyme

Cofactor? Retrieved from news-medical.net:

https://www.news-medical.net/life-sciences/What-is-an-

Enzyme-

Cofactor.aspx#:~:text=Some%20enzymes%20require%20th

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