Enzymes PDF

Enzymes  Enzymes Most enzymes are proteins Enzyme action Enzymes contain two cofactors: 1- Lock and key model metal ions and vitami...

Enzymes  Enzymes Most enzymes are proteins Enzyme action Enzymes contain two cofactors: 1- Lock and key model metal ions and vitamins An enzyme binds a substrate region called the active site Only certain substrate can fit the active site Enzyme-substrat complex forms Imp The enzyme name should end with - ase Substrate should be same shape as active site Example : Sucrase - reacts sucrose Products is released Lipase - reacts with lipids But Digestive Enzymes ends With - in Example: Pepsin, trypsin and chemotrypsin Factors effect the enzyme action: 1- temperature 2- induced fit model Little activity at low temperature Enzyme structure is flexible not rigid Rate increases with temperature Active site adjust shape to bind substrate Most active At optimum temperature (37) Substrate reacts to form product Activity lost with desaturation at high temperature 2- pH Maximum activity at optimum pH Most lose activity in Low or high PH 3- substrate concentration Increasing substrate concentration increases the rate of reaction Maximum activity reached when all of A. The active site is enzyme combines with substrate (1) the enzyme (2) a section of the enzyme (3) the substrate Sucrase has an optimum temperature of 37°C and an optimum pH of 6.2. Determine the effect of the B. In the induced fit model, the shape of following on its rate of reaction the enzyme when substrate binds (1) Stays the same (1) no change (2) increase (3) decrease (2) adapts to the shape of the substrate A. Increasing the concentration of sucrose B. Changing the pH to 4 C. Running the reaction at 70°C  Classification of enzymes 1- oxidoreductoase Enzyme inhibition: A+B: = A:+B (Removes hydrogen from a substrate) 1- Competitive inhibition Oxidation - reduction Has a structure Similar to substrate 2- transferases Occupies active site A+B(With active group) = A(with active group)+B (Transfer group of atoms) Compete with substrate for active site Has effect reversed by increasing substrate concentration 3- hydrolases AB+H2O = A+B (Hydrolysis) 4- lyases AB = A+B (Add/Remove atoms to form double bond) 5- Isomerases AB = BA (Rearrange atoms) 2- Noncompetitive inhibition Does not have a structure like the substrate 6- Ligases Binds to the enzyme not the active site A+B = AB (Combine molecules using ATP) Change the shape of the enzyme und the active site Substrate cannot fit alerted active site No reaction occurs Effect is not reversed by adding substrate