In the viral replicative cycle, what reaction do viral proteases catalyze? Select True or False for each statement. T/F They catalyze polymerization of amino acids into peptides. T/F They catalyze folding of long peptide chains into functional proteins. T/F They catalyze cutting of polyprotein chains into functional proteins. T/F They catalyze breaking of peptide bonds

Verified step by step guidance

1. Understand the role of viral proteases: Viral proteases are enzymes that specifically target and cleave peptide bonds within a polyprotein. This cleavage is crucial for the maturation of the virus, as it converts the polyprotein into functional viral proteins.
2. Analyze the first statement: 'They catalyze polymerization of amino acids into peptides.' This process describes the formation of peptides, which is actually carried out by ribosomes during protein synthesis, not by proteases. Therefore, this statement is False.
3. Evaluate the second statement: 'They catalyze folding of long peptide chains into functional proteins.' Protein folding is generally assisted by molecular chaperones rather than proteases. Proteases are involved in cleaving peptide bonds, not in assisting with the folding process. Thus, this statement is False.
4. Assess the third statement: 'They catalyze cutting of polyprotein chains into functional proteins.' This is the primary function of viral proteases. They cleave the long polyprotein chain into individual functional proteins necessary for the viral lifecycle. Hence, this statement is True.
5. Consider the fourth statement: 'They catalyze breaking of peptide bonds.' This statement is essentially describing the action of proteases, which cleave peptide bonds within proteins or polyproteins. Therefore, this statement is True.

Key Concepts

Viral Proteases

Viral proteases are enzymes produced by viruses that play a crucial role in their replicative cycle. They catalyze the cleavage of polyproteins into smaller, functional proteins necessary for viral replication and assembly. This process is essential for the maturation of viral particles, allowing them to become infectious.

Polyprotein Processing

Many viruses express their proteins as a single, large polyprotein that must be cleaved into individual functional proteins. This processing is facilitated by viral proteases, which recognize specific cleavage sites within the polyprotein. The resulting proteins include structural components and enzymes vital for the viral life cycle.

Peptide Bonds

Peptide bonds are the covalent linkages that connect amino acids in a protein. During the action of viral proteases, these bonds are broken to release individual peptides from the polyprotein. Understanding peptide bond dynamics is essential for grasping how proteins are formed and modified during viral replication.