Question

Which of the following acts as a serene protease that, with cofactors, cleaves C3b and C4b?

A. DAF (CD55)
B. Properdin
C. Factor H
D. Factor I
E. MCP (CD46)

Answer 1

The serine protease that cleaves C3b and C4b with the assistance of cofactors is Factor I. Factor I is part of the complement system, which helps to clear pathogens and promote inflammation.

Step-by-step explanation:

The serine protease that, with cofactors, cleaves C3b and C4b is Factor I. Both C3b and C4b are important components in the complement system, which is a part of the immune system that enhances the ability to clear microbes and damaged cells from an organism, promotes inflammation, and attacks the pathogen's cell membrane. Factor I requires a cofactor for its activity, and cofactors include MCP (CD46), Factor H, and DAF (CD55). Nevertheless, Factor I is the enzyme responsible for the cleavage of C3b and C4b, with the assistance of these cofactors.

Answer 2

The serene protease that, with cofactors, cleaves C3b and C4b is D. Factor I.

Step-by-step explanation:

In the complex cascade of the complement system, Factor I plays a pivotal role as a serene protease. It acts in conjunction with cofactors to cleave C3b and C4b, crucial components in the immune response. The complement system is a sophisticated network of proteins that play a key role in the body's defense against pathogens. Factor I, when activated with its cofactors, serves as a precision instrument, ensuring controlled and targeted cleavage of C3b and C4b.

D. Factor I works in harmony with various regulators such as DAF (CD55), MCP (CD46), and Factor H to maintain a delicate balance in the immune response.

The collaboration between these regulatory proteins prevents unnecessary activation of the complement system and protects the host cells from inadvertent damage. The enzymatic activity of Factor I involves the cleavage of specific peptide bonds, leading to the inactivation of C3b and C4b. This controlled proteolysis is essential for preventing excessive inflammation and tissue damage while ensuring an effective immune response.

Understanding the specific interactions and enzymatic activities of complement proteins, such as Factor I, provides insights into the intricate mechanisms of the immune system. The orchestration of these components underscores the body's ability to mount a precise and regulated defense against invading pathogens, highlighting the remarkable complexity and elegance of the immune response.