Podcast
Questions and Answers
What is the effect of temperature on enzyme action up to the optimum temperature?
What is the effect of temperature on enzyme action up to the optimum temperature?
At what temperature range do most human enzymes optimally function?
At what temperature range do most human enzymes optimally function?
What happens to the enzyme reaction rate after surpassing the optimum temperature?
What happens to the enzyme reaction rate after surpassing the optimum temperature?
Which of the following factors affects enzyme activity by altering the ion concentration in the environment?
Which of the following factors affects enzyme activity by altering the ion concentration in the environment?
Signup and view all the answers
What is the optimal pH range for most enzymes functioning in the human body?
What is the optimal pH range for most enzymes functioning in the human body?
Signup and view all the answers
What is the effect of pH on enzyme activity?
What is the effect of pH on enzyme activity?
Signup and view all the answers
Which enzyme has an optimum pH below neutral?
Which enzyme has an optimum pH below neutral?
Signup and view all the answers
What role does activation energy play in enzyme activity?
What role does activation energy play in enzyme activity?
Signup and view all the answers
What is the pH optimum for pepsin to maintain maximum enzymatic activity?
What is the pH optimum for pepsin to maintain maximum enzymatic activity?
Signup and view all the answers
What happens to the reaction rate when substrate concentration increases, according to enzyme kinetics?
What happens to the reaction rate when substrate concentration increases, according to enzyme kinetics?
Signup and view all the answers
Which ion is known to activate salivary amylase?
Which ion is known to activate salivary amylase?
Signup and view all the answers
In the Michaelis-Menten equation, what does Km represent?
In the Michaelis-Menten equation, what does Km represent?
Signup and view all the answers
What occurs when the pH of an enzyme-catalyzed reaction moves away from its optimum pH?
What occurs when the pH of an enzyme-catalyzed reaction moves away from its optimum pH?
Signup and view all the answers
Which enzyme is characterized by low Km and acts effectively at low substrate concentrations?
Which enzyme is characterized by low Km and acts effectively at low substrate concentrations?
Signup and view all the answers
Why is the Lineweaver-Burk plot useful in enzyme kinetics?
Why is the Lineweaver-Burk plot useful in enzyme kinetics?
Signup and view all the answers
How does the concentration of coenzymes influence enzymatic reactions?
How does the concentration of coenzymes influence enzymatic reactions?
Signup and view all the answers
What is the effect of substrate concentration on the rate of an enzyme-catalyzed reaction?
What is the effect of substrate concentration on the rate of an enzyme-catalyzed reaction?
Signup and view all the answers
What effect do competitive inhibitors have on enzyme activity?
What effect do competitive inhibitors have on enzyme activity?
Signup and view all the answers
In enzyme kinetics, what characterizes enzymes with a high Km?
In enzyme kinetics, what characterizes enzymes with a high Km?
Signup and view all the answers
What can contribute to the decrease in enzyme reaction rate over time?
What can contribute to the decrease in enzyme reaction rate over time?
Signup and view all the answers
Which enzyme's activity is influenced by pH in a way that the enzyme denatures outside its optimal environment?
Which enzyme's activity is influenced by pH in a way that the enzyme denatures outside its optimal environment?
Signup and view all the answers
What is typically plotted on the Y-axis of a Michaelis-Menten plot?
What is typically plotted on the Y-axis of a Michaelis-Menten plot?
Signup and view all the answers
What is the effect of metal ion activators on enzymatic reactions?
What is the effect of metal ion activators on enzymatic reactions?
Signup and view all the answers
What is the primary challenge when directly plotting Vi versus [S] in enzyme kinetics?
What is the primary challenge when directly plotting Vi versus [S] in enzyme kinetics?
Signup and view all the answers
Study Notes
Factors Affecting Enzyme Activity
- Enzyme activity is influenced by various factors, impacting the rate of reactions they catalyze.
- Key factors affecting enzyme activity are: temperature, pH, concentration of coenzymes, concentration of ion activators (metals), enzyme concentration, substrate concentration, and inhibitors.
- Time also impacts enzyme activity, as substrate concentration diminishes over time and end products may accumulate, leading to negative feedback inhibition on enzyme activity. Changes in pH, away from the optimum, also affect reaction rate.
Temperature
- Increasing temperature generally accelerates enzyme activity up to an optimum temperature.
- Optimum temperature: The temperature where enzyme activity is highest, maximizing the conversion of substrate to products.
- The optimum temperature for human enzymes typically lies between 37-40°C.
- Above the optimum temperature, enzyme activity decreases due to denaturation (60-65°C).
- Increased temperature initially increases kinetic energy of substrates, reducing activation energy, and accelerating collisions between molecules.
pH
- Each enzyme exhibits optimal activity at a specific pH range.
- Pepsin's optimal pH is 1.5-2.0.
- Pancreatic enzymes operate optimally at 7.5-8.0.
- Salivary amylase functions best around pH 6.8.
- The optimal pH range for most enzymes is 7.35-7.45.
- Significant deviations from the optimal pH cause enzyme denaturation, impacting function.
- pH changes affect ionization of enzyme and substrate amino acid side chains in the active site; this alters the enzyme's structure and can disable catalysis.
Time
- Enzyme-catalyzed reactions slow down over time.
- This is due to: the depletion of substrate, buildup of product which can cause feedback inhibition (some products can inhibit the initial reaction), and changes in pH moving away from the optimum.
Enzyme and Coenzymes/ Co-factors
- Increased coenzyme concentration leads to a corresponding increase in reaction rate for those enzymes requiring coenzymes.
- Increased activator metal ion concentration leads to increased reaction rate of enzymes requiring those ions.
Enzyme Concentration
- The rate of enzyme-catalyzed reactions is directly proportional to the enzyme concentration. This relationship holds true when substrate is abundant and other conditions remain constant.
Substrate Concentration
- Increasing substrate concentration initially increases the reaction rate, reaching a maximum rate known as Vmax.
- At Vmax, all enzyme active sites are saturated with substrate, and further increases in substrate concentration will not affect reaction rate.
Inhibitors
- Inhibitors reduce or stop enzyme activity.
- Competitive inhibitors compete with substrates, binding to the active site.
- Non-competitive inhibitors bind to sites other than the active site, affecting enzyme functionality.
Enzyme Kinetics
- Enzyme kinetics deals with the rates of enzymatic reactions.
- The Michaelis-Menten equation describes the relationship between initial reaction rate (Vi) and substrate concentration ([S]) featuring a constant called the Michaelis constant (Km):
- Vi = (Vmax [S]) / ([S] + Km)
Michaelis-Menten Plot
- This plot depicts the relationship between reaction velocity and substrate concentration.
- It is difficult to measure Vmax and Km precisely from this plot.
Michaelis Constant (Km)
- Km represents the substrate concentration where the reaction rate is half of the maximal velocity (Vmax).
- Higher Km values mean the enzyme has a lower affinity for its substrate, requiring a higher substrate concentration for half-maximal activity.
- Lower Km values indicate higher affinity of the enzyme for its substrate.
Enzymes with Low/High Km
- Enzymes with low Km have a high affinity for their specific substrates, showing maximal activity at relatively low substrate concentrations.
- Conversely, enzymes with high Km show low affinity for their substrates, exhibiting high activity only at high substrate concentrations.
Lineweaver-Burk Plot
- Linear plot representing the reciprocal of the Michaelis-Menten equation.
- Vmax and Km calculation from the plot is more precise compared to the original Michaelis-Menten plot.
Enzyme Inhibitors
- Inhibitors are substances that reduce or stop enzyme activity.
- Competitive inhibitors bind to the active site.
- Non-competitive inhibitors bind to a site other than the active site, altering enzyme shape.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Related Documents
Description
Explore the key factors influencing enzyme activity in this quiz. You'll learn about temperature, pH, concentration levels, and how these elements affect enzymatic reactions. Dive into the science of enzymes and test your knowledge on their operational dynamics.
