Reaction: UDP-α-D-galactose + a 1,2-diacyl-sn-glycerol = UDP + a 1,2-diacyl-3-O-(β-D-galactosyl)-sn-glycerol
For diagram click here.
Other name(s): uridine diphosphogalactose-1,2-diacylglycerol galactosyltransferase; UDP-galactose:diacylglycerol galactosyltransferase; MGDG synthase; UDP galactose-1,2-diacylglycerol galactosyltransferase; UDP-galactose-diacylglyceride galactosyltransferase; UDP-galactose:1,2-diacylglycerol 3-β-D-galactosyltransferase; 1β-MGDG; 1,2-diacylglycerol 3-β-galactosyltransferase; UDP- galactose:1,2-diacyl-sn-glycerol 3-β-D-galactosyltransferase
Systematic name: UDP-α-D-galactose:1,2-diacyl-sn-glycerol 3-β-D-galactosyltransferase
Comments: This enzyme adds only one galactosyl group to the diacylglycerol; EC 2.4.1.241, digalactosyldiacylglycerol synthase, adds a galactosyl group to the product of the above reaction. There are three isoforms in Arabidopsis that can be divided into two types, A-type (MGD1) and B-type (MGD2 and MGD3). MGD1 is the isoform responsible for the bulk of monogalactosyldiacylglycerol (MGDG) synthesis in Arabidopsis [4].
Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, PDB, CAS registry number: 37277-55-7
References:
1. Veerkamp, J.H. Biochemical changes in Bifidobacterium bifidum var. pennsylvanicus after cell-wall inhibition. VI. Biosynthesis of the galactosyldiglycerides. Biochim. Biophys. Acta 348 (1974) 23-34. [PMID: 4838219]
2. Wenger, D.A., Petipas, J.W. and Pieringer, R.A. The metabolism of glyceride glycolipids. II. Biosynthesis of monogalactosyl diglyceride from uridine diphosphate galactose and diglyceride in brain. Biochemistry 7 (1968) 3700-3707. [PMID: 5681471]
3. Miège, C., Maréchal, E., Shimojima, M., Awai, K., Block, M.A., Ohta, H., Takamiya, K., Douce, R. and Joyard, J. Biochemical and topological properties of type A MGDG synthase, a spinach chloroplast envelope enzyme catalyzing the synthesis of both prokaryotic and eukaryotic MGDG. Eur. J. Biochem. 265 (1999) 990-1001. [PMID: 10518794]
4. Benning, C. and Ohta, H. Three enzyme systems for galactoglycerolipid biosynthesis are coordinately regulated in plants. J. Biol. Chem. 280 (2005) 2397-2400. [PMID: 15590685]