TY - JOUR
AU - Voragen, Alphons
AB -  Galactosyltransferases (GalTs), capable of transferring a galactosyl residue from UDP-galactose (UDP-Gal) to polysaccharide acceptor, were solubilized from flax (Linum usitatissimum L.) membranes using 0.5% CHAPS. The observed requirement for a rhamnogalacturonan I (RG-I) exogenous substrate to stimulate the solubilized GalT activity provided the first evidence for the presence of RG-I GalT activities in flax cells. An assay to measure specifically the products of this RG-I GalT activity was designed, based on size-exclusion chromatography. Labelled products were characterized as an RG-I polymer by using purified RG-I hydrolase or lyase. At pH 8 and in the presence of 5 mM CaCl2, β-D-galactosyl residues were specifically transferred onto RG-I branches of short β-(1→4)-D-galactan side chains. These side chains were liable to hydrolysis by β-galactosidase and endo-β-(1→4)-D-galactanase. The RG-I GalT had a temperature optimum of 30 °C, an apparent K
m for UDP-Gal and exogenous RG-I substrate of 460±40 µM and 1.1±0.1 mg ml–1 respectively, and a V
max of 3.0±0.5 pkat mg–1 protein.
TI - Solubilization of rhamnogalacturonan I galactosyltransferases from membranes of a flax cell suspension
JF - Planta
DO - 10.1007/s004250100539
DA - 2001-07-24
UR - https://www.deepdyve.com/lp/springer-journals/solubilization-of-rhamnogalacturonan-i-galactosyltransferases-from-JmsLjqqrF2
SP - 435
EP - 445
VL - 213
IS - 3
DP - DeepDyve
ER -