Purification and characterization of altered cystic fibrosis liver α‐L‐fucosidase

Abstract

α‐L‐Fucosidase (E.C.3.2.1.51) from two cystic fibrosis livers has been purified and characterized. Purification was accomplished by an affinity chromatographic procedure previously used for normal liver α‐L‐fucosidase. Characterization of the two cystic fibrosis α‐L‐fucosidases indicated that they were very similar to normal liver α‐L‐fucosidase with regard to pH optima profiles, Michaelis constants (Km's), subunit structure and antigenicity. However, gas liquid chromatographic analysis revealed altered carbohydrate compositions for both the cystic fibrosis α‐L‐fucosidases. The three major sugars found in normal purified liver α‐L‐fucosidase (mannose, N‐acetylglucosamine and sialic acid) were reduced in the cystic fibrosis α‐L‐fucosidases, on average, to 51 %, 44 % and 32 %, respectively, of their normal amounts,

Physicochemical Characterization and Biological Activity of Intrinsic Factor in Cystic Fibrosis

“…In fact, the sialic acid content of IF purified from cystic fibrosis gastric juice was lower than that of IF purified from normal gastric juice. After a comparison of the isoprotein pattern of purified and unpurified IF, it can be concluded that the difference in sialic acid content of IF is the result of a desialylation by endogenous sialidase during the purification, and not the result of a modified glycosylation, as was observed for o-t-fucosidase (30). An increased sialidase activity has been previously reported in cystic fibrosis meconium (31).…”