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Introduction of enzymes

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Introduction of enzymes

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Introduction of enzymes

  1. 1. INTRODUCTION OF ENZYMES & MODELS ENZYME SUBSTRATE COMPLEX FORMATION
  2. 2. PRESENTED BY: Muhammad Arshad Malik MBBS First Year Hashmat Medical College
  3. 3. WHAT ARE ENZYMES? • Catalyst of biological system • Protein in nature • Increase the rate of reaction without being used
  4. 4. CATALYTIC ACTIVITY OF ENZYMES • Enzymes have immense power to accelerate the ate of reaction by reducing activation energy • Activation energy is the minimum amount of energy required to start the chemical reaction. • It can be decreased by increasing the temperature of reaction medium
  5. 5. PROTEIN NATURE OF ENZYME • All enzymes are proteins in nature having large molar weight • Few enzyme are simple proteins while some are conjugated proteins in nature • Enzymes are consist of two parts: protein part and non protein part. • Protein part is called Apo enzyme while non protein is called co enzyme or prosthetic group • Combination of apoenzyme and co enzyme is called holoenzyme
  6. 6. MONOMERIC ENZYME & OLIGOMERIC ENYMES • Monomeric enzymes consist of one polypeptide chain • Example ribonuclease • Oligomeric enymes are consist of more than one poly peptide chains • Example hexokinase • Single chain of oligomeric enzyme is called subunit
  7. 7. SPECIFITY OF ENZYME • Optical specifity • There can be many optical isomers of substrate but only one of the isomers act as substrate for enzyme action • Reaction specifity • One enzyme can catalyze specific reaction only • E.g. oxaloacetic acid can undergo many reation sbut each reaction is catalyze by specific enzyme
  8. 8. MODEL OF ENZYME SUBSTRATE COMPLEX • There are two modals enzyme substrate complex • Lock and key modal • Active site is rigid and preshaped. Substrate fits into active site of enzyme like key fits into lock. • This modal is not accepted because it is unable to explain changes in enzyme activity.
  9. 9. MODEL OF ENZYME SUBSTRATE COMPLEX • Induce fit modal • According to this modal, active site is not rigit. It is flexible in nature. When substrate fits into active site of enzyme, it produce changes in active site structure.
  10. 10. Thanks You All

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