Question

Which of the following is a negatively charged sugar or sugar derivative?

• A. \(\beta\)-D-Galactosamine
• B. N-Acetylmuramic acid
• C. \(\beta\)-D-Mannosamine
• D. D-Gluconate

Hint:

Gluconate: oxidized glucose with carboxylate group.
Negatively charged at physiological pH.
Amino sugars: may be positively charged.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
Some sugar derivatives have charged groups.
The charge depends on the functional groups present.

Step 2: Key Formula or Approach:
No specific formula.
Need to know the structures of sugar derivatives.

Step 3: Detailed Explanation:
D-Gluconate is the oxidized form of glucose.
It has a carboxylate group, which is negatively charged.
\(\beta\)-D-Galactosamine and \(\beta\)-D-Mannosamine are amino sugars.
They may be positively charged or neutral depending on pH.
N-Acetylmuramic acid has a carboxylate group but also an amide.
Thus, D-Gluconate is negatively charged.

Step 4: Final Answer:
D-Gluconate is a negatively charged sugar derivative.
Hence, the correct option is (D).