title: Decreased GlcNAc 6-O-sulfotransferase activity in the cornea with macular corneal dystrophy.
abstract: OBJECTIVE
  Macular corneal dystrophy (MCD) is an autosomal recessive inherited disorder that is accompanied by corneal opacity. Explants from MCD-affected corneas have been reported to synthesize low-sulfated KS, suggesting that sulfate groups attached to KS may play critical roles in maintaining corneal transparency. To clear the biosynthetic defect in the MCD cornea, sulfotransferase activities were determined that are presumably involved in the biosynthesis of KS: galactose-6-sulfotransferase (Gal6ST) activity and N-acetylglucosamine 6-O-sulfotransferase (GlcNAc6ST) activity.
  
  
  METHODS
  Gal6ST and GlcNAc6ST activities, which were contained in the corneal extracts from corneas affected by MCD and keratoconus and from normal control corneas, were determined by measuring the transfer of (35)SO(4) from [(35)S]3'-phosphoadenosine 5'-phosphosulfate into the Gal residue of partially desulfated KS and the nonreducing terminal GlcNAc residue of GlcNAcbeta1-3Galbeta1-4GlcNAc (oligo A), respectively.
  
  
  RESULTS
  The level of Gal6ST activity in corneal extracts from eyes with MCD, which was measured by using partially desulfated KS as an acceptor, was nearly equal to that in eyes with keratoconus and normal control eyes. In contrast, GlcNAc6ST activity in the extracts from MCD-affected corneas, which was measured by using oligo A as an acceptor, was much lower than in those in corneas with keratoconus and in normal control corneas.
  
  
  CONCLUSIONS
  The decrease in GlcNAc6ST activity in the cornea with MCD may result in the occurrence of low- or nonsulfated KS and thereby cause corneal opacity.
authors.affiliation: Department of Life Science, Aichi University of Education, Division of Pathobiology, Juntendo University, School of Medicine, Tokyo, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Hasegawa
authors.forename: T
authors.initials: T
authors.lastname: Torii
authors.forename: T
authors.initials: T
authors.lastname: Kato
authors.forename: H
authors.initials: H
authors.lastname: Miyajima
authors.forename: A
authors.initials: A
authors.lastname: Furuhata
authors.forename: K
authors.initials: K
authors.lastname: Nakayasu
authors.forename: A
authors.initials: A
authors.lastname: Kanai
authors.forename: O
authors.initials: O
authors.lastname: Habuchi
mesh_terms: D000328:Adult; D000368:Aged; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D002854:Chromatography, Paper; D003315:Cornea / Q000201:enzymology*; D003317:Corneal Dystrophies, Hereditary / Q000201:enzymology* / Q000601:surgery; D005260:Female; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D007632:Keratan Sulfate / Q000096:biosynthesis; D007640:Keratoconus / Q000201:enzymology / Q000601:surgery; D015948:Keratoplasty, Penetrating; D008297:Male; D008875:Middle Aged; D015238:Sulfotransferases / Q000378:metabolism*; D000097811:Carbohydrate Sulfotransferases
chemical_list: D007632:Keratan Sulfate; D015238:Sulfotransferases; D000097811:Carbohydrate Sulfotransferases