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SPECIFICITY OF ENZYME

Mechanism of Enzyme - Substrate Specificity
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Learning objectives: 
I Understand enzyme specificity
I Importance of enzyme specificity
I Classification of enzyme ...
SPECIFICITY OF ENZYMES ' .  

EASY BIOLOGY CIA”

  

Introduction

I Enzymes are biological catalysts

I Almost all enzyme...
SPECIFICITY 0E ENZYMES 

What is enzyme specificity? 
C Ability of an enzyme to choose exact substrate
F It is a molecular...
SPECIFICITY OE ENZYMES

 

Different types of enzyme specificity
Enzymes shows different degree of specificity,  grouped in...
SPECIFICITY oE ENZYMES 

( 1).  Bond specificity: 
F Specific to substrates having similar bonds and similar structures
_ _...
SPECIFICITY OF ENZYMES

(2).  Group spec1'ficity: 

 

I Enzyme specific to type of bond and groups surrounding it
I More s...
SPECIFICITY OF ENZYMES

(2).  Group specificity: 

 

Trypsin hydrolyze a peptide bond in which amino group is contributed ...
SPECIFICETY OF ENZYIVIES

(2).  Group specificity: 

Aminopeptidase hydrolyzes the peptide bond form N terminal of protein
...
SPECIFICITY OF ENZYMES ' . ‘ 

IAN BIOLOGY QM? 

  

( 3 ).  Substrate specificity
I Enzyme specific to only one substrate ...
SPECIFICETY OF ENZYMES

(4).  Optical specificity

Also called stereo-specificity

Enzyme are specific not only to substrate...
SPECIFICITY OF ENZYMES

(4).  Optical speci'ficity

 

I D—amino acid oxidase acts only on D—amino acids

I oi—glycosidic b...
SPECIFICETY OF ENZYMES

(5).  Geometrical specificity
Ft Here specificityis less
rf Enzyme can act on different substrates...
SPECIFICITY OF ENZYMES ' .  5

  

EASY BIOLOGV (LAOS

(6).  Co-factorspecificity

I Specificity is high

I Here enzyme are...
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Specificity of Enzyme (Specific Activity of Enzyme) PPT by easybiologyclass Slideshare

Enzyme specificity definition
Definition of enzyme substrate specificity and different types of enzyme
specificity. bond specificity, Group specificity, substrate specificity,

stereo specificity, optical specificity, geometrical specificity, cofactor

specificity

Enzymes are biological catalysts. They accelerate the rate of metabolic

reactions in the cells by reducing the activation energy of the reactants.

Almost all enzymes are specialized proteins with definite structural

conformations. Important characteristic features of enzyme are:
1. Catalytic Power (ratio of enzyme catalyzed rate of a reaction to

the un-catalyzed rate)
2. Regulation (control of enzymatic reaction)
3. Specificity (Selectivity of enzyme to their substrate)
Enzyme specificity
Specificity is the ability of an enzyme to choose exact substrate from a

group of similar chemical molecules. The specificity is actually a

molecular recognition mechanism and it operates through the structural and

conformational complementarity between enzyme and substrate. Enzymes show

different degrees of specificity towards their substrate.
The specificities shown by enzymes are grouped into 6 categories
1. Bond specificity
2. Group specificity
3. Substrate specificity
4. Stereo specificity (Optical specificity)
5. Geometrical specificity
6. Co-factor specificity
Bond specificity is also called as relative specificity. Enzymes showing

bond specificity are specific to substrates having similar bonds and

similar structure
It is also called moderate specificity. Here the enzyme is specific to a

bond and groups surrounding the bonds. Group specificity is more than that

of bond specificity. Endopeptidases and exopeptidases (two general classes

of proteinases) are classical examples for group specificity.
Substrate specificity is also called as absolute specificity, since here

the specificity is very high. Enzymes showing substrate specificity are

specific only to one substrate and one reaction.
Optical specificity of enzyme is also called as stereo-specificity. Here

the enzyme is specific not only to substrate but also to its optical

configuration. Optical specificity of enzyme is considered as the highest

specificity shown by any class of enzyme in the living world.
In geometrical specificity, single enzyme can act on different substrates

having similar molecular geometry and hence here specificity is very less.

Example: Alcohol dehydrogenase can oxidize both ethanol and methanol to

yield corresponding aldehydes since both these alcohols have similar

molecular geometry.
(6). Co-factor specificity
Co-factors are non-protein part of enzyme required for the functioning of

some enzymes. Enzyme which requires co-factors for their activity shows

co-factor specificity. Only correct combination of substrate and co-factor

allows enzymatic reaction. In the absence of specific co

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Specificity of Enzyme (Specific Activity of Enzyme) PPT by easybiologyclass Slideshare

  1. 1. SPECIFICITY OF ENZYME Mechanism of Enzyme - Substrate Specificity
  2. 2. 7 , .- . I . .__ 1 r _ I —‘ . . . /{.251 "There is more to life than increasing its speed. ..” Mahatma Gandhi www. easybiologyclass. com Is)
  3. 3. 7 . ).m Learning objectives: I Understand enzyme specificity I Importance of enzyme specificity I Classification of enzyme specificity I Different types of enzyme specificity: - @. Bond specificity @. Group specificity @. Substrate specificity @. Optical or Stereo specificity @. Geometrical specificity ,3- @. Co-factor specificity wwm easybiologyclass. com . —. - . I . *Lr _
  4. 4. SPECIFICITY OF ENZYMES ' . EASY BIOLOGY CIA” Introduction I Enzymes are biological catalysts I Almost all enzymes are specialized proteins I Ribozymes are the exception (they are RNA with catalytic properties) I Important characteristic features of enzyme are: > Catalytic Power (ratio of enzyme catalyzed rate of a reaction to the un-catalyzed rate) > Regulation (control of enzymatic reaction) > Spec1ficity(SeIectiVity of enzyme to their substrate)
  5. 5. SPECIFICITY 0E ENZYMES What is enzyme specificity? C Ability of an enzyme to choose exact substrate F It is a molecular recognition mechanism F Recognition and specificity is based on structural complementarity Conformational Complementarity of Enzyme and Substrate Substrate Enzyme Enzyme Conformational Asymmetry of Similar Conformational Symmetry of Enzyme and Substrate Enzyme and Substrate www. easybiologyclass. com on
  6. 6. SPECIFICITY OE ENZYMES Different types of enzyme specificity Enzymes shows different degree of specificity, grouped into 6 categories 1. Bond specificity 2. Group specificity 3. Substrate specificity 4 Optical or Stereo specificity 5. Geometrical specificity 6. Co-factor specificity www. easybiologyclass. com
  7. 7. SPECIFICITY oE ENZYMES ( 1). Bond specificity: F Specific to substrates having similar bonds and similar structures _ _ _ _ Bond Specificityofl-Inzyme rf Spec1f1c1ty1s less Peptide Bond P fd B d C Also called relative specificity ep 1 9 on I I Glycine -(ll-'~ - Glycine Alanine —E—‘. — Valine . ‘ Enzyme Enzyme Example , Peptidase enzyme are spcci fit to llflllllllt bond formed between any amino acids V Amylase can hydrolyze or-1-4 glycosidic linkage in starch and glycogen F Lipase can hydrolyze ester bond between glycerol and fatty acid in any fats W Proteinases hydrolyzes all peptide bonds formed by any amino acids www. easybiologyclass. com
  8. 8. SPECIFICITY OF ENZYMES (2). Group spec1'ficity: I Enzyme specific to type of bond and groups surrounding it I More specificity than bond specificity I Also called moderate specificity and structural specificity I Endopeptidases and exopeptidaces are classical examples Example: Pepsin hydrolyze a peptide bond in which the amino group is contributed by an aromatic amino acid (phenyl alanine, tyrosine and tryptophan) Pepsin Cleavage Sites C- Terminal N- Terminal
  9. 9. SPECIFICITY OF ENZYMES (2). Group specificity: Trypsin hydrolyze a peptide bond in which amino group is contributed by a basic amino acid (lysine, arginine and histidine) Trypsin Cleavage Sites N- Terminal ‘ 6- Terminal Chymotrypsin hydrolyze a peptide bond in which the carboxyl group is contributed by an aromatic amino acid (phenylalanine, tyrosine and tryptophan) Chymotrypsin Cleavage Sites N- Terminal Terminal
  10. 10. SPECIFICETY OF ENZYIVIES (2). Group specificity: Aminopeptidase hydrolyzes the peptide bond form N terminal of protein Aminopeptidase Cleavage Site _ N- Terminal C’ Te""'"“I . ~. uf . (3% ‘I'D j ': l'-I ‘T H j (‘A3 ? "‘ '1 ? ‘K1: j Carboxypeptidase hydrolyzes the peptide bond from C terminal of protein N- Terminal 0 Terminal www. easybiologyclass. com 1 0
  11. 11. SPECIFICITY OF ENZYMES ' . ‘ IAN BIOLOGY QM? ( 3 ). Substrate specificity I Enzyme specific to only one substrate and one reaction I Specificity is high I Also called absolute specificity I Example: I Lactase acts only on lactose I Sucrase act only on sucrose I Maltase acts only on maltose
  12. 12. SPECIFICETY OF ENZYMES (4). Optical specificity Also called stereo-specificity Enzyme are specific not only to substrate but also to its optical configuration Specificity is very high Example: L-amino acid oxidase acts only on L-amino acids Stereo specificity of En’/ .ymcs / “‘ l, ‘ L” 4:’ % K 7 , " ‘ . _/ | (/1 IL: " —_ C. — ‘ — Cc — I H " *1 ‘ . Enzyme I -M ~ Enzyme L-Alanine Oxidase & I. -Alanine Oxidase & L-Alanine D-Alanine www. easybiologyclass. com
  13. 13. SPECIFICITY OF ENZYMES (4). Optical speci'ficity I D—amino acid oxidase acts only on D—amino acids I oi—glycosidic bonds of starch and glycogen are hydrolyzed only by (X- glycosidase (oi-amylase) I [3-glycosidic bonds of cellulose are hydrolyzed only by B-glycosidase (B- amylase) Stereo specificity of Enzymes av-1-4 Linked 3'14 Linked Glucose (starch) Glucose (Cellulose) < i i >. ,< > q 0 é o S 7 . a-Amylase a-Amylase
  14. 14. SPECIFICETY OF ENZYMES (5). Geometrical specificity Ft Here specificityis less rf Enzyme can act on different substrates having similar molecular geometry F7 Example: Alcohol dehydrogenase can oxidize ethanol, methanol and propanol to yields corresponding aldehydes Geometric specificity of Eiizyines Methanol Ethanol ; A »sr ;9 /6‘ / O /6' / o 6' '/ Oo I9 0/’ Enzyme 6‘ 6‘ Enzyme ’“"°"°'_ De”-Vd’°9°"“5e Alcohol Dehydrogenase Amng °" Ethaml Acting on Methanol wwmeasybiologyclass. com 14
  15. 15. SPECIFICITY OF ENZYMES ' . 5 EASY BIOLOGV (LAOS (6). Co-factorspecificity I Specificity is high I Here enzyme are specific to substrate and co-factor I Only correct combination of substrate & co-factor allow enzymatic reaction I In the absence of specific co-factor, the enzyme will be inactive even if there are plenty of substrates
  16. 16. Formore iiifbnnation, please log on to: WW" VV . easybiologyclass. C O In For Video tutorials please subscribe the You Tube clianiiel: You 1 easybiologyclass ‘Ilian&‘You. . . E-mail us @: ._. _ easybiologyclass@gmail. com ° 0 mail@easybiologyclass. com I’ _ visit: www. easybiologyclass. com

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