CHAPTER 3 - ENZYMES
ENZYMES - protein molecules which can be defined as a biological catalysis
- globular protein (coiled into a 3D shape with hydrophilic R group on the
outside)
- have active site (a cleft which substrate bind into)
INTRACELLULAR EXTRACELLULAR
-operate within cells, e.g catalase -secreted by cells and catalyse
reactions outside cells e.g digestive
enzymes in the gut
LOCK & KEY HYPOTHESIS
-the shape of the active site allows substrate to fit perfectly
-enzyme molecules is rigid and not flexible
-LEKS > Lock Enzyme Key Substrate
INDUCED FIT HYPOTHESIS
-enzyme molecules are flexible
-the shape of the active site can change slightly as the substrate interacts with the
active site of the enzyme
ACTIVATION ENERGY
-the amount of energy required to start off a chemical reaction
-makes it easier to convert substrate to product
-enzyme reduce activation energy
, FACTOR THAT AFFECT ENZYME ACTION
1) ENZYME CONCENTRATION
1. The concentration of enzymes increase, the frequency of successful
collisions between enzyme and substrate increase
2. The number of active sites increases so the number of enzyme-substrate
complexes increases. Therefore, rate of reaction increase
3. At a certain point, the number of enzyme molecules is greater than substrate
molecules. The increase in enzyme concentration beyond this point will not
increase the rate of reaction. Hence, substrate concentration is the limiting
factor now
2) SUBSTRATE CONCENTRATION
1. The concentration of substrate increase, the frequency of successful
collisions between substrate and enzyme increase as more substrate can
occupy free active sites of the enzymes
ENZYMES - protein molecules which can be defined as a biological catalysis
- globular protein (coiled into a 3D shape with hydrophilic R group on the
outside)
- have active site (a cleft which substrate bind into)
INTRACELLULAR EXTRACELLULAR
-operate within cells, e.g catalase -secreted by cells and catalyse
reactions outside cells e.g digestive
enzymes in the gut
LOCK & KEY HYPOTHESIS
-the shape of the active site allows substrate to fit perfectly
-enzyme molecules is rigid and not flexible
-LEKS > Lock Enzyme Key Substrate
INDUCED FIT HYPOTHESIS
-enzyme molecules are flexible
-the shape of the active site can change slightly as the substrate interacts with the
active site of the enzyme
ACTIVATION ENERGY
-the amount of energy required to start off a chemical reaction
-makes it easier to convert substrate to product
-enzyme reduce activation energy
, FACTOR THAT AFFECT ENZYME ACTION
1) ENZYME CONCENTRATION
1. The concentration of enzymes increase, the frequency of successful
collisions between enzyme and substrate increase
2. The number of active sites increases so the number of enzyme-substrate
complexes increases. Therefore, rate of reaction increase
3. At a certain point, the number of enzyme molecules is greater than substrate
molecules. The increase in enzyme concentration beyond this point will not
increase the rate of reaction. Hence, substrate concentration is the limiting
factor now
2) SUBSTRATE CONCENTRATION
1. The concentration of substrate increase, the frequency of successful
collisions between substrate and enzyme increase as more substrate can
occupy free active sites of the enzymes
