the mechanisms of enzyme function and inhibition (1)

THE MECHANISMS OF ENZYME FUNCTION AND INHIBITION

GROUP 2

GROUP MEMBERS• Phan Duc Anh • Nguyen Hien Huy Hoang• Vu Thi My Linh• Nguyen Pham Thang Long• Nguyen Duc Thanh• Nguyen Thi Bao Tran• Nguyen Quynh An Trang• Nguyen Vu Hoang Uyen

CONTENTS• INTRODUCTION•MECHANISM OF ENZYME FUNCTION•MECHANISM OF ENZYME INHIBITION•CONCLUSION•REFERENCES

INTRODUCTION• Enzymes are proteins, they work as biological

catalysts.

INTRODUCTION• The function of enzymes is to accelerate the

rate of reactions. • Enzymes are not consumed by the reaction.

INTRODUCTION• Enzyme inhibitors are used to prevent enzymes

from working. When Enzyme cofactors required for some enzymes to work.• Applying these

knowledge to make poisons or therapeutic substances.

MECHANISM OF ENZYME FUNCTION

• There are several types of catalytic mechanisms of enzyme.

Acid – base catalysis Covalent catalysis Metal ion catalysis Catalysis by approximation

MECHANISM OF ENZYME FUNCTION

Lock and key model

Induced-fit model

MECHANISM OF ENZYME INHIBITION

• Non-specific • Specific Irreversible

Group-specific Affinity label Suicide

Reversible Competitive Non-competitive Uncompetitive


• Non-specific: any physical (temperature) or chemical (acid and base) changes. Denature the enzymes

• Non-specific inhibitors affect all kind of enzymes in the same way.


• Irreversible: Inhibitors bind (covalently or non-covalently) to the enzyme so tightly permanently block the enzyme’s activity.

• The binding site could be at, near, or remote from the active site.

IRREVERSIBLE

INHIBITORS

Suicide

Affinity label

Group- specific

reagents react with specific side chains of amino acids

are molecules that are structurally similar to the

substrate for an enzyme and that covalently bind to

active-site residues

get activated upon binding with the active site of

specific enzyme by a few steps of the biochemical reaction with no product


• Competitive inhibitors: The inhibitor competes with the substrate for the same active site.


• Non-competitive inhibitors: A noncompetitive inhibitor is a substance that interacts with the enzyme OR enzyme-substrate complex.


• Un-competitive inhibitors: un-competitive inhibitors just ONLY bind to the enzyme-substrate complex.

CONCLUSION• Enzymes are biological catalysts which are proteins

• Functions of enzymes are to increase the reaction rate

• Inhibitors could be just to impair the function of enzymes

REFERENCES• Jeremy M. Berg, John L. Tymoczko, Lubert Stryer and Gregory

J. Gatto, Jr. Biochemistry. 7th edition. New York: W. H. Freeman and Company, 2012.

• Donald Voet, Judith G. Voet and Charlotte W. Pratt. Fundamentals of Biochemistry: Life at the Molecular Level, 3th edition. The United State of America: KendallVille, 2008

• Geoffrey M. Cooper. The Cell: A Molecular Approach. 2nd edition. Sinauer Associates, 2000

• Enzyme, Wikipedia. 2013http://en.wikipedia.org/wiki/Enzyme (Accessed 06-Oct-2013)• http://www.ncbi.nlm.nih.gov/books/NBK9921/

the mechanisms of enzyme function and inhibition (1)

Documents