lecture 1 Enzymes.ppt
- Количество слайдов: 52
Вiochemistry of enzymes
Enzyme Classifcation 1. Oxidoreductases 2. Transferases 3. Hydrolases 4. Lyases 5. Isomerases 6. Ligases
The overall Coenzyme role Coenzyme A Activation and transfer of acyl groups Pyridoxal transfer phosphate of amino groups FAD Transfer of hydrogen (electrons) Vitamin precursor Pantothenic acid Pyridoxine - Vitamin B 6 Riboflavin Vitamin B 2
coenzyme binding domain inactive enzyme vitamin active enzyme
Enzyme active site
Molecule of trypsin with amino acid residues in the active site
Allosteric enzyme
Multifunctional enzyme
Isozymes of lactate dehydrogenase
Multimolecular enzyme systems NADPH oxidase
Fumarate inner mitochondrial membrane Succinate matrix intermembrane space I, III and IV – mitochondrial respiratory chain complexes (the electron transport chain)
Hermann Emil Fischer (1852 - 1919)
Lock-and-key model by Fisher E + S E-S E + P
Daniel Koshland (1920 - 2007)
Induced-fit theory by Koshlend
Substrate strain theory
Leonor Michaelis Maud Leonora Menten
Equation of Michaelis - Menten Briggs – Haldane equation:
Lineweaver – Burk plot
Urease CO(NH 2)2 + 2 H 2 O = H 2 O +
Arginase
Pancreatic lipase
Fumarase fumaric acid maleic acid
Regulation of enzyme activity
Enzymatic activity IU = 1 mcmole/min 1 kat = 1 mole/sec 1 IU = 16. 67 nkat
Enzymes activated by metals Enzyme Cytochromes Peroxidase Amylase Phosphatase Cholinesterase Metal Fe Fe Ca Mg Mn
Competitive inhibition
succinate fumarate malonate
Competitive inhibition
p-aminobenzoic acid sulfanilamide
Non-competitive inhibition
Non-competitive inhibition
Un-competitive inhibition
Irreversible competitive inhibition
Irreversible competitive inhibition
Activation of the enzyme by phosphorylation
Regulation of activity by dissociation of the subunits of the enzyme Protein kinase
Partial proteolysis inactive enzyme
Allosteric regulation of enzyme activity
Feedback inhibition
ENZYMES IN MEDICINE
Enzymes as therapeutic agents Enzyme The use of enzymes Trypsin, lipase, Disturbances of the amylase digestion Urease Removal of urea from the body in the "artificial kidney" Ribonuclease, Antiviral drugs against deoxyribonucle herpetic keratitis, ase adenoviral conjunctivitis Streptokinase, Preventing blood clots urokinase during operations
Enzymes as analytical agents Enzyme Glucose oxidase, peroxidase Lipase Cholesterol oxidase Various The use of enzyme Determination of glucose concentrations in the blood Determination of triacylglycerol concentration in the blood Determination of cholesterol in the blood Determination of pyruvate,
(stain)
Indicator enzymes Disease Myocardial infarction Liver diseases Pancreas diseases Enzyme aspartate transaminas e, LDH-1, creatine kinase alanine transaminase, aspartate transaminas e, -glutamyl transferase, alkaline phosphatase amylase, lipase, trypsin