AKSHAYA.pptx this is most advanced metho

AKSHAYA.pptx this is most advanced metho

1. DEFENCE MECHANISM AGAINST HYDROGEN PEROXIDE Akshay Kumar Roul Roll No- 23CY4513

2. Basically in our body Hydrogen peroxide(H 2 O 2 ) is formed by 2 ways. By partial reduction of dioxygen. O 2 O 2 - H 2 O 2 By dismutation of superoxide. Oxidation O 2 - O 2 2- + O 2 Reduction

3. We have to remove it because H 2 O 2 causes oxidative damage in our body, It destroys proteins, nucleic acid etc. So nature creates catalases and peroxidase enzyme to convert it peroxide into H 2 O and other substance. Reduction 2H 2 O 2 2H 2 O + O 2 Oxidation Choice of metal ion for the active center of Catalase and Peroxidase:- H 2 O 2 /H 2 O E ◦ = 0.28 V O 2 /H 2 O 2 E ◦ = +1.23 V Cu 2 + + e- Cu+ E◦ = 0.153 V Fe 3 + + e- Fe 2 + E◦ = 0.77 V

4. Catalase:- Function- 1. It converts H 2 O 2 to dioxygen & H 2 O Oxidation 2H 2 O 2 2H 2 O + O 2 ( Disproportion Reaction) Reduction 2. It Converts H 2 O 2 to useful chemical. 3. It prevents any build up of dehydrous H 2 O 2 in body. Catalase is found in nearly all organism exposed to dioxygen environment.

5. Oxidation state of Fe is +3. It contains Heme b unit (Heme = Fe + Porphyrin) Axial ligand phenolate unit of Tyrosine residue Fe3+ is in High spin state. Structure of active site of catalase:- Radical cation intermediate Porphyrin ring is oxidizes by 1 electron. Fe is in Fe4+ state. Low spin complex. It’s color is green due to the Porphyrin radical cation.

6. Reaction:- P Fe(III) + H 2 O 2 P Fe(III) (H 2 O 2 ) (P+)Fe(IV)O+H 2 O (Heterolytic cleavage) Radical cation intermediate (P+)Fe(IV)O+H 2 O 2 P Fe(III) + H 2 O +O 2 Peroxidase:- Function- It converts organic & inorganic substances into useful chemicals by using H 2 O 2 It also prevents any build up of toxic H 2 O 2 in body.

7. THANK YOU….