Coenzymes

Coenzymes


COENZYMES

  • Coenzyme derived from water soluble vitamins.
  • Coenzymes function as- 
  1. Co- substrates- In a group transfer reaction coenzyme acts either a donar or acceptor. Most common mechanism of coenzymes.
  2. Prosthetic groups- coenzyme covalently bound to enzyme. 

Classification of Coenzyme

a. For transfer groups other than hydrogen-

Vitamin

Coenzyme

Function as Coenyme

 

Entity transferred

Riboflavin (Vit B2)

FAD, FMN

Oxidation & reduction reaction

Hydrogen atoms

Niacin

NAD+, NADH+

Oxidation & reduction rxn

Hydride ion

Pyridoxin (Vit B6)

Pyridoxial phosphate (PLP)

Decarboxylation of amino acids

Amino group

Folic acid

Tetrahydrofolate

Carrier of one carbon group

One carbon group

Pentothenic acid

Coenzyme A

Acyl carrier

Acyl group

Cyanocobalamine

Methylcobalamine &Deoxyadenosylcobalamine

Transfer of H2 group & isomerization

Alkyl group or hydrogen atom

 b. For transfer of hydrogen- Lippoic acid

Metalloenzymes (Cofactors)-

Metal

Metalloenzymes

Copper (Cu+2/Cu+)

Cytochrome oxidase, Lysyl oxidase, ceruloplasmin

Iron (Fe+2/Fe+)

Xanthine oxidase

Zinc (Zn+2)

Carbonic anhydrase, alkaline phosphatase, alcohol dehydrogenase, carboxypeptidase, glutamate dehrdogenase, lactate dehdrogenase, superoxide dismutase

Magnesium (Mg+2)

Phosphatases, kinase, glutathione synthase

Selenium

Glutathione peroxidise

Molybdenum

Xanthine oxidase, sulphite oxidase

Exam Question
 
  1. Co- substrates- In a group transfer reaction coenzyme acts either a donar or acceptor. Most common mechanism of coenzymes.
  2. Non protein- chemical components are organic molecules(coenzyme)
  3. Classification of coenzymes-For transfer of hydrogen- Lippoic acid
  4. Zinc- carbonic anhydrase, Alcohol dehydrogenase
  5. Metalloenzymes (Cofactors)-

    Metal

    Metalloenzymes

    Copper (Cu+2/Cu+)

    Cytochrome oxidase, Lysyl oxidase, ceruloplasmin

    Iron (Fe+2/Fe+)

    Xanthine oxidase

    Zinc (Zn+2)

    Carbonic anhydrase, alkaline phosphatase, alcohol dehydrogenase, carboxypeptidase, glutamate dehrdogenase, lactate dehdrogenase, superoxide dismutase

    Magnesium (Mg+2)

    Phosphatases, kinase, glutathione synthase

    Selenium

    Glutathione peroxidise

    Molybdenum

    Xanthine oxidase, sulphite oxidase

  6. Vitamin

    Coenzyme

    Function as Coenyme

    Entity transferred

    Riboflavin (Vit B2)

    FAD, FMN

    Oxidation & reduction reaction

    Hydrogen atoms

    Niacin

    NAD+, NADH+

    Oxidation & reduction rxn

    Hydride ion   Coenzyme for pyruvate dehydrogenase- NADPH

    7. Coenzyme for Glucose-6 phosphate dehydrogenase- NADP

    8. Coenzyme for malate dehydrogenase- NAD+

    9. Coenzyme for pyruvate dehydrogenase- NADPH

Don’t Forget to Solve all the previous Year Question asked on Coenzymes

Module Below Start Quiz

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