Vmax & the Michaelis-Menten Constant Substrate concentration?affects the?rate of catalysis?in an enzyme-substrate reaction When the substrate concentration is?fixed?(and enzyme concentration is...
Rate: Inhibitor Concentration There are?two types?of inhibitors: Competitive?inhibitors have a?similar shape?to that of the?substrate?molecules and therefore?compete?with the substrate for the acti...
Rate: Enzyme Concentration Enzyme concentration affects the rate of reaction The?higher?the?enzyme concentration?in a reaction mixture, the?greater the number of active sites?available and the?grea...
Rate: pH All enzymes have an?optimum pH?or a pH at which they operate best Enzymes are?denatured?at extremes of pH Hydrogen?and ionic bonds?hold the tertiary structure of the protein (ie. the enzym...
Rate: Temperature Enzymes have a?specific optimum temperature?– the temperature at which they catalyse a reaction at the?maximum rate Lower temperatures?either?prevent?reactions from proceeding or?...
Colorimetry to Measure Enzyme Activity A?colorimeter?is able to measure?light absorbance?(how much light is absorbed) or?light transmission?(how much light passes through) a substance Colorimetry c...
Measuring Enzyme Activity The?progress?of?enzyme-catalysed reactions?can be investigated by: Measuring the?rate of formation of a product?using catalase Measuring the?rate of disappearance of a sub...
How Enzymes Work The lock-and-key hypothesis Enzymes are?globular proteins This means their?shape?(as well as the shape of the?active site?of an enzyme) is determined by the complex tertiary struct...
Mode of Enzyme Action Enzymes have an?active site?where?specific substrates bind?forming an?enzyme-substrate complex The?active site?of an enzyme has a?specific shape?to fit a specific substrate Ex...
