Immunoglobulins Explained: Structure, Classes, and Functions

Immunoglobulins Explained: Structure, Classes, and Functions

Question 1. Immunoglobulin
Answer:

• They are specialized groups of proteins

Immunoglobulin Structure:

• Consists of 2 heavy chains and 2 light chains
• These chains are held together by disulfide bonds
• Thus it forms Y shaped structure
• Heavy chains are linked to carbohydrates

Immunoglobulin Classes:

• They are named according to the heavy chain they contain

Question 2. What is S adenosyl methionine? How is it formed and what is its importance?
Answer:

S adenosyl methionine:

• It is sulfur-containing amino acids

S adenosyl methionine Formation:

• It is formed by a transmethylation reaction
• It occurs by the transfer of an adenosyl group from ATP to a sulfur atom of methionine by the methionine S adenosyl transferase enzyme
• As a result, sulfur becomes a sulfonium atom
• 3 ATP molecules are consumed in it

S adenosyl methionine Significance:

• Transfer methyl group to an acceptor from methionine
• Hydrolyses to homocysteine – remethylated to methionine by N- methyl tetrahydrofolate
• S adenosyl methionine is also involved in the synthesis of polyamines like spermine

Question 3. Name different types of immunoglobulin and their functions, (or) Structure and functions of immunoglobulin.
Answer:

Immunoglobulin:

• All immunoglobulin consists of two identical heavy chains and two light chains held together by disulfide bonds.
• The variable region is present at the amino-terminus while the constant region is at the carboxy-terminal.
• Based on the heavy chain, immunoglobulin is classified into 5 classes.