Which of the following enzymes is responsible for the conversion of UDP-N-acetylglucosamine to UDP-N-acetylgalactosamine, a key step in the synthesis of ABO blood group antigens?

A Galactosyltransferase
B N-acetylgalactosamine transferase
C UDP-N-acetylglucosamine 4'-epimerase ✓
D Fucosyltransferase

Explanation

UDP-N-acetylglucosamine 4'-epimerase is the enzyme responsible for converting UDP-N-acetylglucosamine to UDP-N-acetylgalactosamine, which is then used as a substrate for the synthesis of ABO blood group antigens.

Source

Biochemistry textbooks
Hematology Hematology: Blood Grouping and Crossmatching Hematology: Blood Grouping and Crossmatching Medium MEDICAL Confidence: medium