1. 1. Al Martini is a 44-year-old man who has been an alcoholic for the past 5 years. He was recently admitted to the hospital for congestive heart failure . After being released from the hospital, he continued to drink. One night he arrived at a friends house at 7:00 P.M. Between his arrival and 11:00 P.M., he drank four beers and five martinis (for a total ethanol consumption of 9.5 oz). His friends encouraged him to stay an additional hour and drink coffee to sober up. Nevertheless, he ran his car off the road on his way home. He was taken to the emergency room of the local hospital and arrested for driving under the influence of alcohol. His blood alcohol concentration at the time of his arrest was 240 mg/dL, compared with the legal limit of ethanol for driving of 80 mg/dL.
2. 2. Specificity !!!
3. 3. Active Site
4. 4. Explanation of the figure
5. 5. Binding of substrate in Active site
6. 6. Conformational change resulting from the binding of glucose to hexokinase. A. Free enzyme. B.With glucose bound, the cleft closes, forming the ATP binding site. The closure of the cleft when glucose binds to hexokinase (or human glucokinase) is one of the largest induced fits known.
7. 7. Enzyme-catalyzed reaction Energy diagram showing the energy levels of the substrates as they progress toward products in the absence of enzyme. The substrates must pass through the high-energy transition state during the reaction. Although a favorable loss of energy occurs during the reaction, the rate of the reaction is slowed by the energy barrier to forming the transition state. The energy barrier is referred to as the activation energy.
8. 8. ENZYMES ARE CLASSIFIED BY REACTION TYPE & MECHANISM
9. 9. Continued
10. 10. MCQs
11. 11. Apoenzyme - protein part of the enzyme Coenzyme (prosthetic group)-nonprotein part Holoenzyme -protein part + nonprotein part
12. 12. Coenzymes are complex nonprotein organic molecules that participate in catalysis by providing functional groups, much like the amino acid side chains. Coenzymes can be divided into two general classes: activation-transfer coenzymes oxidation-reduction coenzymes.
13. 13. activation-transfer coenzymes Thiamine pyrophosphate (TPP) Coenzyme A (CoA) Biotin Pyridoxal phosphate oxidation-reduction coenzymes. NAD+ (nicotinamide adenine dinucleotide) FAD (Flavin adenine dinucleotide ) NADP+ (nicotinamide adenine dinucleotide phosphate) FMN (Flavin mononucleotide )
14. 14. Coenzymes
15. 15. Regulation of enzymes
16. 16. Km Km Km of the enzyme for a substrate is defined as the concentration of substrate at which vi equals 12 Vmax. Km (hexokinase) - 0,05mM Km (glucokinase) > 5mM
17. 17. Clinical comment
18. 18. Dont forget Km differences of enzymes Alcohol Dehydrogenases
19. 19. Regulation of enzymes Regulation by Substratesand products Allosteric regulation Covalent modification Inhibition
20. 20. Regulation of enzymes
21. 21. Inhibition Irriversible Reversible Competitive Noncompetitive uncompetitive
22. 22. Mcq
23. 23. ENZYMES FACILITATE DIAGNOSIS OF DISEASES Principal serum enzymes used in clinical diagnosis. Many of the enzymes are not specific for the disease listed
24. 24. THANK YOU