Вiochemistry of enzymes The overall Coenzyme role

Вiochemistry of enzymes

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