Biosynthesis of galactogen: identification of a beta-(1----6)-D-galactosyltransferase in Helix pomatia albumen glands

Biochim Biophys Acta. 1989 Sep 15;992(3):289-97. doi: 10.1016/0304-4165(89)90087-1.

Abstract

A beta-(1----6)-D-galactosyltransferase has been purified over 2000-fold by affinity chromatography on UDP-p-aminophenyl-Sepharose. The enzyme, from a pellet fraction (8000 x g) of Helix pomatia albumen gland, catalyzes transfer of D-galactose from UDP-galactose to a (1----6) linkage on acceptor H. pomatia galactogen. Three other polymers served as acceptors: beef lung galactan, Lymnaea stagnalis galactogen and arabinogalactan from larch wood. To determine the linkage specificity of the enzyme, it was incubated with UDP-D-galactose and acceptor galactogen that had been tritiated previously by treatment with galactose oxidase and [3H]KBH4. The [3H]galactogen reaction product was recovered, methylated, hydrolyzed and acetylated; tritiated derivatives were identified by mass spectroscopy of effluent fractions separated by gas chromatography. This analysis revealed that (1----6)-linked galactosyl groups had been added to the enzyme-treated acceptor galactogen. Also identified was a hydrolytic enzyme that removed terminal alpha 1,2-linked L-galactosyl residues from H. pomatia galactogen.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Chromatography, Affinity
  • Chromatography, High Pressure Liquid
  • Galactans / biosynthesis*
  • Galactosyltransferases / isolation & purification
  • Galactosyltransferases / metabolism*
  • Helix, Snails / enzymology*
  • Kinetics
  • Molecular Weight
  • Sebaceous Glands / enzymology
  • Substrate Specificity

Substances

  • Galactans
  • galactogen
  • Galactosyltransferases
  • UDP-beta(1-6)-D-galactosyltransferase