Transferase Activity of Lactobacillal and Bifidobacterial ?-Galactosidases with Various Sugars as Galactosyl Acceptors.

ABSTRACT: The ?-galactosidases from Lactobacillus reuteri L103 (Lreu?gal), Lactobacillus delbrueckii subsp. bulgaricus DSM 20081 (Lbul?gal), and Bifidobacterium breve DSM 20281 (Bbre?gal-I and Bbre?gal-II) were investigated in detail with respect to their propensity to transfer galactosyl moieties onto lactose, its hydrolysis products D-glucose and D-galactose, and certain sugar acceptors such as N-acetyl-D-glucosamine (GlcNAc), N-acetyl-D-galactosamine (GalNAc), and L-fucose (Fuc) under defined, initial velocity conditions. The rate constants or partitioning ratios (kNu/kwater) determined for these different acceptors (termed nucleophiles, Nu) were used as a measure for the ability of a certain substance to act as a galactosyl acceptor of these ?-galactosidases. When using Lbul?gal or Bbre?gal-II, the galactosyl transfer to GlcNAc was 6 and 10 times higher than that to lactose, respectively. With lactose and GlcNAc used in equimolar substrate concentrations, Lbul?gal and Bbre?gal-II catalyzed the formation of N-acetyl-allolactosamine with the highest yields of 41 and 24%, respectively, as calculated from the initial GlcNAc concentration.

SUBMITTER: Arreola SL 

PROVIDER: S-EPMC4819807 | biostudies-literature | 2016 Mar

REPOSITORIES: biostudies-literature