Question

A protein without its prosthetic group is known as:

• A. apoprotein
• B. hemoprotein
• C. holoprotein
• D. lipoprotein

Hint:

Remember: apo = without; holo = whole. Apoprotein lacks the group; holoprotein has it.

Answer 1

The Correct Option is A

A prosthetic group is a non-protein component tightly bound to a protein and essential for its biological activity. Proteins that require prosthetic groups (such as heme, metal ions, or organic molecules) can exist in two forms depending on whether the group is attached.

Step 1: Understand key terms.
- Apoprotein: Protein portion alone, without its prosthetic group.
- Holoprotein: Active form of the protein with its prosthetic group bound.
- Hemoprotein: A protein containing heme, not a general category.
- Lipoprotein: A protein bound to lipids, unrelated to the definition here.

Step 2: Match terms with definition.
Since the question asks specifically about a protein without its essential prosthetic group, the correct biochemical term is apoprotein.

Step 3: Conclusion.
Therefore, the protein without its prosthetic group is known as an apoprotein.