IMMUNOCHEMICAL PROPERTIES OF HUMAN PLASMA α1 → 2 FUCOSYLTRANSFERASE SPECIFIED BY BLOOD GROUP H‐GENE

Abstract

A β‐galactoside α1 → 2 fucosyltransferase (H‐enzyme) from human group O plasma which provides H blood group specificity to erythrocyte membranes has been purified approximately 22,000‐fold by chromatography on DEAE‐Sepharose CL‐6B, GDP‐hexanolamine‐Sepharose 4B and SP‐Sephadex C‐50. The molecular weight of the H‐enzyme was estimated to be 150,000 by gel filtration. Human group O erythrocyte membranes which had lost their H blood group activity by the action of α1 → 2 fucosidase were fucosylated by the transferase, and restored the H activity. Radioactive _L‐fucose appeared to be incorporated into glycolipid blood group substances of erythrocyte membranes. The activity of the α1 → 2 fucosyltransferase from human plasma, stomach mucosa, erythrocyte membranes and porcine stomach mucosa were specifically inhibited by the rabbit antiserum immunized with the preparation of human plasma H‐enzyme. The anti‐plasma H‐enzyme antiserum did not inhibit the activities of α1 → 3 N‐acetygalactosaminyltransferase (A‐enzyme), α1 → 3 galactosyltransferase (B‐enzyme), and β‐N‐acetylglucosaminide α1 → 3 and α1 → 4 fucosyltransferases from human plasma and stomach mucosa.