KEGG   ENZYME: 2.4.1.184Help
Entry
EC 2.4.1.184                Enzyme                                 

Name
galactolipid galactosyltransferase;
galactolipid-galactolipid galactosyltransferase;
galactolipid:galactolipid galactosyltransferase;
interlipid galactosyltransferase;
GGGT;
DGDG synthase (ambiguous);
digalactosyldiacylglycerol synthase (ambiguous);
3-(beta-D-galactosyl)-1,2-diacyl-sn-glycerol:mono-3-(beta-D-galactosyl)-1,2-diacyl-sn-glycerol beta-D-galactosyltransferase;
3-(beta-D-galactosyl)-1,2-diacyl-sn-glycerol:3-(beta-D-galactosyl)-1,2-diacyl-sn-glycerol beta-D-galactosyltransferase
Class
Transferases;
Glycosyltransferases;
Hexosyltransferases
BRITE hierarchy
Sysname
1,2-diacyl-3-O-(beta-D-galactosyl)-sn-glycerol:1,2-diacyl-3-O-(beta-D-galactosyl)-sn-glycerol beta-D-galactosyltransferase
Reaction(IUBMB)
2 a 1,2-diacyl-3-O-(beta-D-galactosyl)-sn-glycerol = a 1,2-diacyl-3-O-[alpha-D-galactosyl-(1->6)-beta-D-galactosyl]-sn-glycerol + a 1,2-diacyl-sn-glycerol [RN:R04472]
Reaction(KEGG)
Substrate
a 1,2-diacyl-3-O-(beta-D-galactosyl)-sn-glycerol
Product
1,2-diacyl-3-O-[alpha-D-galactosyl-(1->6)-beta-D-galactosyl]-sn-glycerol;
1,2-diacyl-sn-glycerol [CPD:C00641]
Comment
By further transfers of galactosyl residues to the digalactosyldiacylglycerol, trigalactosyldiacylglycerol and tetragalactosyldiacylglycerol are also formed. This enzyme was originally thought to be the major enzyme involved in the production of digalactosyldiacylglycerol in plants as it masked the effect of the true enzyme (EC 2.4.1.241, digalactosyldiacylglycerol synthase) [4,5]. Its activity is localized to chloroplast envelope membranes, but it does not contribute to net galactolipid synthesis in plants [4].
History
EC 2.4.1.184 created 1990, modified 2005
Pathway
Glycerolipid metabolism
Metabolic pathways
Reference
1
  Authors
Dorne, A.-J., Block, M.A., Joyard, J. and Douce, R.
  Title
The galactolipid-galactolipid galactosyltransferase is located on the outer surface of the outer-membrane of the chloroplast envelope.
  Journal
FEBS Lett. 145 (1982) 30-34.
Reference
2
  Authors
Heemskerk, J.W.M., Wintermans, J.F.G.M., Joyard, J., Block, M.A., Dorne, A.-J. and Douce, R.
  Title
Localization of galactolipid:galactolipid galactosyltransferase and acyltransferase in outer envelope membrane of spinach chloroplasts.
  Journal
Biochim. Biophys. Acta 877 (1986) 281-289.
Reference
3
  Authors
Heemskerk, J.W.M., Jacobs, F.H.H. and Wintermans, J.F.G.M.
  Title
UDPgalactose-independent synthesis of monogalactosyldiacylglycerol. An enzymatic activity of the spinach chloroplast envelope.
  Journal
Biochim. Biophys. Acta 961 (1988) 38-47.
Reference
4  [PMID:14600212]
  Authors
Kelly AA, Froehlich JE, Dormann P.
  Title
Disruption of the two digalactosyldiacylglycerol synthase genes DGD1 and DGD2 in Arabidopsis reveals the existence of an additional enzyme of galactolipid synthesis.
  Journal
Plant. Cell. 15 (2003) 2694-706.
  Organism
Arabidopsis thaliana
Reference
5  [PMID:15590685]
  Authors
Benning C, Ohta H.
  Title
Three enzyme systems for galactoglycerolipid biosynthesis are coordinately regulated in plants.
  Journal
J. Biol. Chem. 280 (2005) 2397-400.
  Organism
Arabidopsis sp.
Other DBs
ExplorEnz - The Enzyme Database: 
IUBMB Enzyme Nomenclature: 
ExPASy - ENZYME nomenclature database: 
BRENDA, the Enzyme Database: 
CAS: 
66676-74-2

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