Identification of a UDP-Gal:beta-galactoside beta 1----3-galactosyltransferase in the albumen gland of the snail Lymnaea stagnalis.

Detergent extracts of the albumen gland of the snail Lymnaea stagnalis contain an enzyme activity that transfers Gal from UDP-Gal to acceptor substrates with terminal non-reducing beta-galactose residues. The products formed with lactose (Gal beta 1----4Glc) as the acceptor were characterized by HPLC, and subjected to 400-MHz 1H-NMR and methylation analysis. The main product was shown to have the structure Gal beta 1----3Gal beta 1----4Glc. Therefore, the galactosyltransferase can be identified as a UDP-Gal:beta-galactoside beta 1----3-galactosyltransferase. In view of its linkage and acceptor specificity, the enzyme may be essential to the biosynthesis of galactogen, the main polysaccharide produced by albumen glands of L. stagnalis.