Download MBBS (Bachelor of Medicine, Bachelor of Surgery) 1st year (First Year) Biochemistry ppt lectures Topic 10 Enzymes Introduction And Mechanism Notes. - biochemistry notes pdf, biochemistry mbbs 1st year notes pdf, biochemistry mbbs notes pdf, biochemistry lecture notes, paramedical biochemistry notes, medical biochemistry pdf, biochemistry lecture notes 2022 ppt, biochemistry pdf.
Enzymes Introduction
and Mechanism of
Action
Learning Objectives
Characteristics of Enzymes
Classification of Enzymes
Nomenclature of Enzymes
Active site and Transition state
Mechanism of enzyme actions
Clinical Importance
Diagnosis and prognosis of diseases.
Disorders: genetic, nutritional, tissue damage
Pharmacologic agents and Gene Therapy
Drugs /Antibiotics.
Enzymes
Enzymes are specialized proteins that function in
the acceleration of chemical reactions
Exception?
Ribozymes
Characteristics of enzyme catalysts
Increase rate of reaction by factor of 106
Highly selective and specific
Not changed as a result of catalysis
Does not change the equilibrium constant
Enzymes Alter Only the Reaction Rate
and Not the Reaction Equilibrium
Cofactor containing enzymes
Examples of coenzymes and cofactors
Vitamin
Coenzyme
Enzymes
Enzymes
Cofactors
Thiamine
TPP
Transketolase,
Ferroxidase
Copper
pyruvate
Dehydrogenase
Riboflavin
FAD, FMN
Succinate
Carbonic anhydrase
Zinc
dehydrogenase
Niacin
NAD,NADP
Malate
Cytochrome oxidase
Copper,
dehydrogenase
Iron
Pyridoxine
PLP
transaminases
Hexokinase
Magnesium
Folic acid
THF
One carbon
Glutathione peroxidase
Selenium
metabolism
Pantothenic acid
Coenzyme A Pyruvate
Arginase
Manganese
dehydrogenase
Xanthine Oxidase
Molybeden
Classification of Enzymes
Nomenclature of Enzymes
International Union of Biochemistry and Molecular
Biology (IUBMB)
Recommended name
Systematic name EC1.1.1.27 (Lactate
Dehydrogenase)
Special names
Phosphatase vs Phosphorylase
Synthetase vs Synthase
Dehydrogenase vs Oxidase vs Oxygenase
Active site
Active
Site
Binding
Catalytic
site
site
Features of Active Site
3D cleft formed by groups that come from different
parts of the amino acid sequence
takes up a relatively small part of the total volume
of an enzyme
clefts or crevices
Substrates are bound to enzymes by multiple weak
attractions
Transition state
Enzymes lower activation energy by stabilizing
transition state
The active site can provide catalytic groups that
enhance the probability that the transition state
is formed
1. LOCK-AND-KEY MODEL FOR SUBSTRATE BINDING: Emil
Fisher
2. "INDUCED FIT" MODEL FOR SUBSTRATE BINDING: Daniel E
koshland
Mechanism of catalysis
1. Catalysis by Proximity
2. Catalysis by strain
Chymotrypsin
3. Acid Base Catalysis
4.Covalent Catalysis
5. Metal ion catalysis
Metal ion catalysis
Assist in binding of the substrate,
Stabilize developing anions in the reaction.
Accept and donate electrons in oxidation-
reduction reactions.
Serine protease like chymotrypsin : acid base
catalysis as well as covalent catalysis
RNAase : covalent catalysis
Metal ion: carbonic anhydrase
Clinical scenario 1
Vitamin B6 responsive and unresponsive
cystathionuria: two variant molecular forms
Clinical Scenario 2
A child was born with inherited mutation in an
enzyme, so that it is unable to bind its coenzyme.
As a result,
(A) the enzyme doesnot bind to its subtrate
(B) the enzyme will not be able to form transition
state complex
(C) the reaction will proceed with free coenzyme
(D) the enzyme will use some other coenzyme
References
Victor W. Rodwell, David A. Bender, Kathleen M. Botham,
Peter J. Kennelly, P. Anthony Weil. Harper's Illustrated
Biochemistry, 30th Edition
Denise R. Ferrier; Lippincott Illustrated Reviews
Biochemistry, 7th Edition
Thank You!
This post was last modified on 05 April 2022