Enzyme Structure and Regulation Quiz

Enzyme Structure and Regulation

• Carbonic anhydrase, found in erythrocytes, converts carbon dioxide to carbonic acid with a Zn2+ active site.
• Proteases, including serine, aspartyl, metallo-, and cysteine proteases, degrade proteins and play crucial roles in protein maturation, blood clotting, and protein trafficking.
• Chymotrypsin, a serine protease secreted from the pancreas, cleaves dietary proteins and contains a catalytic triad of Aspartate, Histidine, and Serine.
• Affinity labeling, using reagents like DIPF and TPCK, selectively labels active site residues and can be blocked by competitive inhibitors.
• Enzyme regulation methods include altering gene expression, sequestration of enzymes, and limiting substrate access via covalent modification and allosteric regulation.
• Covalent modification, such as proteolytic cleavage and phosphorylation, activates enzymes like zymogens, the inactive precursors of enzymes.
• Phosphorylation, facilitated by protein kinases and reversed by phosphatases, regulates enzyme activity through signaling cascades.
• Src, regulated by phosphorylation, is an example of protein activation through phosphorylation.
• Allosteric regulation, which increases or decreases enzymatic activity by binding at a site other than the active site, can exist in relaxed (R) and tense (T) states.
• Allosteric enzymes exhibit sigmoidal activity curves, indicating rapid and direct regulation.
• Copyright © 2019 John Wiley & Sons, Inc. All rights reserved. Reproduction or translation of this work beyond that permitted in Section 117 of the 1976 United States Act without the express written permission of the copyright owner is unlawful.
• Request for further information should be addressed to the Permissions Department, John Wiley & Sons, Inc. The purchaser may make back-up copies for his/her own use only and not for distribution or resale. The Publisher assumes no responsibility for errors, omissions, or damages, caused by the use of these programs or from the use of the information contained herein.

Enzyme Structure and Regulation

• Carbonic anhydrase, found in erythrocytes, converts carbon dioxide to carbonic acid with a Zn2+ active site.
• Proteases, including serine, aspartyl, metallo-, and cysteine proteases, degrade proteins and play crucial roles in protein maturation, blood clotting, and protein trafficking.
• Chymotrypsin, a serine protease secreted from the pancreas, cleaves dietary proteins and contains a catalytic triad of Aspartate, Histidine, and Serine.
• Affinity labeling, using reagents like DIPF and TPCK, selectively labels active site residues and can be blocked by competitive inhibitors.
• Enzyme regulation methods include altering gene expression, sequestration of enzymes, and limiting substrate access via covalent modification and allosteric regulation.
• Covalent modification, such as proteolytic cleavage and phosphorylation, activates enzymes like zymogens, the inactive precursors of enzymes.
• Phosphorylation, facilitated by protein kinases and reversed by phosphatases, regulates enzyme activity through signaling cascades.
• Src, regulated by phosphorylation, is an example of protein activation through phosphorylation.
• Allosteric regulation, which increases or decreases enzymatic activity by binding at a site other than the active site, can exist in relaxed (R) and tense (T) states.
• Allosteric enzymes exhibit sigmoidal activity curves, indicating rapid and direct regulation.
• Copyright © 2019 John Wiley & Sons, Inc. All rights reserved. Reproduction or translation of this work beyond that permitted in Section 117 of the 1976 United States Act without the express written permission of the copyright owner is unlawful.
• Request for further information should be addressed to the Permissions Department, John Wiley & Sons, Inc. The purchaser may make back-up copies for his/her own use only and not for distribution or resale. The Publisher assumes no responsibility for errors, omissions, or damages, caused by the use of these programs or from the use of the information contained herein.

Enzyme Structure and Regulation

• Carbonic anhydrase, found in erythrocytes, converts carbon dioxide to carbonic acid with a Zn2+ active site.
• Proteases, including serine, aspartyl, metallo-, and cysteine proteases, degrade proteins and play crucial roles in protein maturation, blood clotting, and protein trafficking.
• Chymotrypsin, a serine protease secreted from the pancreas, cleaves dietary proteins and contains a catalytic triad of Aspartate, Histidine, and Serine.
• Affinity labeling, using reagents like DIPF and TPCK, selectively labels active site residues and can be blocked by competitive inhibitors.
• Enzyme regulation methods include altering gene expression, sequestration of enzymes, and limiting substrate access via covalent modification and allosteric regulation.
• Covalent modification, such as proteolytic cleavage and phosphorylation, activates enzymes like zymogens, the inactive precursors of enzymes.
• Phosphorylation, facilitated by protein kinases and reversed by phosphatases, regulates enzyme activity through signaling cascades.
• Src, regulated by phosphorylation, is an example of protein activation through phosphorylation.
• Allosteric regulation, which increases or decreases enzymatic activity by binding at a site other than the active site, can exist in relaxed (R) and tense (T) states.
• Allosteric enzymes exhibit sigmoidal activity curves, indicating rapid and direct regulation.
• Copyright © 2019 John Wiley & Sons, Inc. All rights reserved. Reproduction or translation of this work beyond that permitted in Section 117 of the 1976 United States Act without the express written permission of the copyright owner is unlawful.
• Request for further information should be addressed to the Permissions Department, John Wiley & Sons, Inc. The purchaser may make back-up copies for his/her own use only and not for distribution or resale. The Publisher assumes no responsibility for errors, omissions, or damages, caused by the use of these programs or from the use of the information contained herein.

Enzyme Kinetics and Inhibition

• Enzyme classifications include oxidoreductases, transferases, hydrolases, lyases, isomerases, and ligases.
• Enzymes lower activation energy to increase reaction rate without changing thermodynamic parameters.
• The Michaelis-Menten equation relates substrate concentration to Vmax and the Michaelis constant (KM).
• Saturation kinetic curve demonstrates enzyme saturation with substrate, influenced by high or low KM values.
• Lineweaver-Burke plot is a double reciprocal of the Michaelis-Menten equation, providing an easier method to interpret graphical data.
• Turnover number (kcat) measures the number of reactions an enzyme can catalyze per unit of time.
• Diffusion-controlled limit occurs when the diffusion of enzyme and substrate becomes the rate-limiting step, with a rate between 10^8 and 10^9 M^-1 sec^-1.
• Inhibitors can be irreversible or reversible, preventing the generation of products.
• Suicide inhibitors directly poison the enzyme by irreversibly modifying the active site, examples include pesticides and nerve agents.
• Competitive inhibition competes directly with the substrate and can be overcome if the substrate concentration is high.
• Uncompetitive inhibition binds to the ES complex, decreasing Vmax and KM.
• Mixed inhibition is a combination of competitive and uncompetitive inhibitors, effective regardless of substrate concentration.

Enzyme Kinetics and Inhibition

• Enzyme classifications include oxidoreductases, transferases, hydrolases, lyases, isomerases, and ligases.
• Enzymes lower activation energy to increase reaction rate without changing thermodynamic parameters.
• The Michaelis-Menten equation relates substrate concentration to Vmax and the Michaelis constant (KM).
• Saturation kinetic curve demonstrates enzyme saturation with substrate, influenced by high or low KM values.
• Lineweaver-Burke plot is a double reciprocal of the Michaelis-Menten equation, providing an easier method to interpret graphical data.
• Turnover number (kcat) measures the number of reactions an enzyme can catalyze per unit of time.
• Diffusion-controlled limit occurs when the diffusion of enzyme and substrate becomes the rate-limiting step, with a rate between 10^8 and 10^9 M^-1 sec^-1.
• Inhibitors can be irreversible or reversible, preventing the generation of products.
• Suicide inhibitors directly poison the enzyme by irreversibly modifying the active site, examples include pesticides and nerve agents.
• Competitive inhibition competes directly with the substrate and can be overcome if the substrate concentration is high.
• Uncompetitive inhibition binds to the ES complex, decreasing Vmax and KM.
• Mixed inhibition is a combination of competitive and uncompetitive inhibitors, effective regardless of substrate concentration.

Enzyme Kinetics and Inhibition

• Enzyme classifications include oxidoreductases, transferases, hydrolases, lyases, isomerases, and ligases.
• Enzymes lower activation energy to increase reaction rate without changing thermodynamic parameters.
• The Michaelis-Menten equation relates substrate concentration to Vmax and the Michaelis constant (KM).
• Saturation kinetic curve demonstrates enzyme saturation with substrate, influenced by high or low KM values.
• Lineweaver-Burke plot is a double reciprocal of the Michaelis-Menten equation, providing an easier method to interpret graphical data.
• Turnover number (kcat) measures the number of reactions an enzyme can catalyze per unit of time.
• Diffusion-controlled limit occurs when the diffusion of enzyme and substrate becomes the rate-limiting step, with a rate between 10^8 and 10^9 M^-1 sec^-1.
• Inhibitors can be irreversible or reversible, preventing the generation of products.
• Suicide inhibitors directly poison the enzyme by irreversibly modifying the active site, examples include pesticides and nerve agents.
• Competitive inhibition competes directly with the substrate and can be overcome if the substrate concentration is high.
• Uncompetitive inhibition binds to the ES complex, decreasing Vmax and KM.
• Mixed inhibition is a combination of competitive and uncompetitive inhibitors, effective regardless of substrate concentration.