ID   2.4.1.241
DE   digalactosyldiacylglycerol synthase.
AN   DGDG synthase.
AN   UDP-galactose:MGDG galactosyltransferase.
AN   UDP-galactose-dependent DGDG synthase.
AN   UDP-galactose-dependent digalactosyldiacylglycerol synthase.
CA   a 1,2-diacyl-3-O-(beta-D-galactosyl)-sn-glycerol + UDP-alpha-D-galactose
CA   = 1,2-diacyl-3-O-[alpha-D-galactosyl-(1->6)-beta-D-galactosyl]-
CA   sn-glycerol + H(+) + UDP.
CC   -!- Diacylglycerol cannot serve as an acceptor molecule for
CC       galactosylation as in the reaction catalyzed by EC 2.4.1.46.
CC   -!- When phosphate is limiting, phospholipids in plant membranes are
CC       reduced but these are replaced, at least in part, by the glycolipids
CC       digalactosyldiacylglycerol (DGDG) and sulfoquinovosyldiacylglycerol.
CC   -!- While both DGD1 and DGD2 are increased under phosphate-limiting
CC       conditions, DGD2 does not contribute significantly under optimal
CC       growth conditions.
CC   -!- DGD2 is responsible for the synthesis of DGDG molecular species that
CC       are rich in C16 fatty acids at sn-1 of diacylglycerol whereas DGD1
CC       leads to molecular species rich in C18 fatty acids.
CC   -!- The enzyme has been localized to the outer side of chloroplast
CC       envelope membranes.
DR   Q9S7D1, DGDG1_ARATH;  Q6DW74, DGDG1_LOTJA;  Q6DW76, DGDG1_SOYBN;
DR   Q8W1S1, DGDG2_ARATH;  Q6DW73, DGDG2_LOTJA;  Q6DW75, DGDG2_SOYBN;
//