Which of the following enzymes is responsible for the conversion of precursor substances into H antigen, the precursor to A and B antigens?

A Fucosyltransferase 1 ✓
B Fucosyltransferase 2
C Galactosyltransferase
D N-Acetylgalactosamine transferase

Explanation

Fucosyltransferase 1 is the enzyme responsible for adding fucose to precursor substances to form H antigen, which can then be converted into A or B antigens by other enzymes.

Source

Biochemistry of Blood Group Antigens article
Hematology Hematology: Blood Grouping and Crossmatching Hematology: Blood Grouping and Crossmatching Medium MEDICAL Confidence: high