Enzymes Part 2 Factors that affect enzyme activity
Enzymes Review • Proteins • Biological catalysts • Speed up a chemical reaction without being used up in the reaction. • Lower the activation energy of the reactants. • Enzymes fit with their substrate like a lock and key. • Forms enzyme substrate complex. • When enzyme bonds, it weakens the chemical bonds of the substrate. • The enzyme is unchanged by the reaction and can be used again.
Induced Fit model • Enzyme changes shape slightly when it comes in contact with the substrate.
Factors that affect enzyme activity • Enzyme Concentration • Substrate concentration • Temperature • pH
Enzyme Concentration • If you increase the enzyme concentration, the rate of reaction will increase to a certain point and then level off. • By increasing the amount of enzymes, you increase the chances of them bumping into a substrate. • The rate levels off because eventually there is not enough substrate for the enzymes to find.
Substrate Concentration • If you increase the substrate concentration, the rate of reaction will increase to a certain point and then level off. • At first, enzymes will run into lots of substrate molecules because they are plentiful.
Temperature • An increase in temperature will increase the rate of reaction until it gets too hot. • Once too hot, the rate of reaction will denature (break down) • Enzyme will no longer fit with the substrate. • Reaction will not occur. • Increasing temp makes molecules move faster. (more likely to bump) • Lower temp makes molecules move slower. (less likely to bump)
ph • 0-6 acid • 8-14 basic • 7 neutral • Each enzyme has an optimal pH. • If pH is not optimal, enzyme will denature (break down) • The enzyme will no longer fit with substrate. • Reaction will not occur.