Proteolysis Flashcards
What is proteolysis?
Proteolysis is the biochemical process of breaking down proteins into smaller peptides or amino acids.
True or False: Proteolysis is essential for protein turnover in cells.
True
Fill in the blank: Proteolysis is primarily carried out by enzymes known as ______.
proteases
What are the two main types of proteolysis?
Endopeptidase and Exopeptidase.
Multiple Choice: Which of the following is NOT a type of protease? A) Serine protease B) Cysteine protease C) Lipase D) Aspartic protease
C) Lipase
What role does proteolysis play in digestion?
It breaks down dietary proteins into amino acids for absorption.
True or False: Proteolysis can occur both intracellularly and extracellularly.
True
Fill in the blank: The process of proteolysis is crucial for ______ regulation.
cellular
What is the function of proteasomes in proteolysis?
Proteasomes degrade ubiquitinated proteins within the cell.
Multiple Choice: Which enzyme class is primarily responsible for cleaving peptide bonds? A) Lipases B) Glycosidases C) Proteases D) Nucleases
C) Proteases
What is the significance of zymogens in proteolysis?
Zymogens are inactive precursors that require activation to become active proteases.
True or False: Proteolysis can lead to the activation of signaling pathways.
True
Fill in the blank: The amino acids released by proteolysis can be used for ______ synthesis.
protein
Multiple Choice: Which of the following conditions can stimulate proteolysis? A) Starvation B) Overeating C) Sleep D) None of the above
A) Starvation
What is the role of lysosomes in proteolysis?
Lysosomes contain proteases that degrade proteins within the cell.
True or False: Proteolysis is only important for protein breakdown.
False
Fill in the blank: Proteolysis is involved in the regulation of ______ and metabolic pathways.
cell cycle
What is the relationship between proteolysis and cancer?
Dysregulation of proteolysis can contribute to cancer progression and metastasis.
Multiple Choice: Which of the following diseases is associated with abnormal proteolysis? A) Alzheimer’s B) Diabetes C) Hypertension D) All of the above
A) Alzheimer’s
What is the role of caspases in proteolysis?
Caspases are proteases that play essential roles in programmed cell death (apoptosis).
True or False: Proteolysis can only occur in the presence of water.
True
Fill in the blank: The degradation of misfolded proteins is a critical function of ______.
proteolysis
What is the effect of proteolysis on cellular signaling?
Proteolysis can activate or deactivate signaling molecules, influencing cellular responses.
Multiple Choice: Which type of protease is involved in blood clotting? A) Serine protease B) Metalloprotease C) Cysteine protease D) Aspartic protease
A) Serine protease
What are the different classifications of proteases?
1) proteases
2) proteinases
3) peptidase
4) cathepsins
What are endopeptidases and exopeptidases?
Endopeptidases- enzymes that break peptide bonds within a protein chain—-> beginning of a chain
Exopeptidases- enzymes that break peptide bonds at the terminal end of a chain
What are aminopeptidases and carboxypeptidases
Aminopeptidases- enzymes that cleave amino acids from N-Terminal of proteins
Carboxypeptidases- enzymes that break down proteins by splitting off amino acids
What is protein activation and protein degradation?
Protein activation- structural/conformational chances to enhance proteins biological activity.
Protein degradation- proteins are broken down into amino acids.
What is protein activation and protein degradation?
Protein activation- structural/conformational chances to enhance proteins biological activity.
Protein degradation- proteins are broken down into amino acids.
Explain protein activation by proteolysis?
This involves the cleavage of specific peptide bonds within a protein—> this leads to structural changes within the protein.
1) Zymogen activation:
-zymogens are enzymes/signalling proteins that are synthesised or inactive precursors.
2) Confirmation changes:
-cleavage allows the protein to adopt an active site, exposing/creating the active site.
3) Regulatory role:
-proteolytic activation serves as a regulatory mechanism this controlling metabolic and physiological processes.
What is ubiquitylation?
Ubiquitylation- involves the attachment of ubiquity (small protein) to a target protein.
Explain the components of the ubiquitinating enzyme complex
Ubiquitin activation enzyme (E1):
-formation of thioester bond between the C-terminus of ubiquitin and a cystein on E1
Ubiquitin-conjugating enzyme (E2):
-transfer of ubiquitin to a cystein on E2
Ubiquitin-protein ligase (E3):
-transfer of ubiquitin (small protein) from E2 to a lysine on a target protein.
Explain the components of the ubiquitinating enzyme complex
Ubiquitin activation enzyme (E1):
-formation of thioester bond between the C-terminus of ubiquitin and a cystein on E1
Ubiquitin-conjugating enzyme (E2):
-transfer of ubiquitin to a cystein on E2
Ubiquitin-protein ligase (E3):
-transfer of ubiquitin (small protein) from E2 to a lysine on a target protein.
Explain the N-End rule
This explains the relationship between protein half life and amino terminal amino acid residue.
N-terminal residues are associated with rapid degradation.
N terminal residues are also tagged for degradation by the ubiquitin-proteasome system
Explain the N-End rule
This explains the relationship between protein half life and amino terminal amino acid residue.
N-terminal residues are associated with rapid degradation.
N terminal residues are also tagged for degradation by the ubiquitin-proteasome system
What class of proteases is involved in the coagulation cascade?
Carboxyproteases.
What is the role of factor IX proprotein?
Zymogen of the clotting cascade
How many proteolytic cleavages are required to convert preproinsulin to mature insulin?
2
