Thus, the two substrates of this enzyme are ADP-glucose and a chain of D-glucose residues joined by 1,4-alpha-glycosidic bonds, whereas its two products are ADP and an elongated chain of glucose residues. Plants use these enzymes in the biosynthesis of starch.
This enzyme belongs to the family of hexosyltransferases, specifically the glycosyltransferases. The systematic name of this enzyme class is ADP-glucose:1,4-alpha-D-glucan 4-alpha-D-glucosyltransferase. Other names in common use include ADP-glucose-starch glucosyltransferase, adenosine diphosphate glucose-starch glucosyltransferase, adenosine diphosphoglucose-starch glucosyltransferase, ADP-glucose starch synthase, ADP-glucose synthase, ADP-glucose transglucosylase, ADP-glucose-starch glucosyltransferase, ADPG starch synthetase, and ADPG-starch glucosyltransferase
Five isoforms seems to be present. GBSS which is linked to amylose synthesis. The others are SS1, SS2, SS3 and SS4. These have different roles in amylopectin synthesis. New work implies that SS4 is important for granule initiation. (Szydlowski et al., 2011)
Structural studiesedit
As of late 2007, 4 structures have been solved for this class of enzymes, with PDB accession codes 1RZU, 1RZV, 2BFW, and 2BIS.
Referencesedit
Chambers J, Elbein AD (1970). "Biosynthesis of glucans in mung bean seedlings. Formation of beta-(1,4)-glucans from GDP-glucose and beta-(1,3)-glucans from UDP-glucose". Arch. Biochem. Biophys. 138 (2): 620–31. doi:10.1016/0003-9861(70)90389-9. PMID 4317490.
FRYDMAN RB, CARDINI CE (1965). "Studies on adenosine diphosphate d-glucose: α-1,4-glucan α-4-glucosyltransferase of sweet-corn endosperm". Biochim. Biophys. Acta. 96 (2): 294–303. doi:10.1016/0926-6593(65)90013-5. PMID 14298833.
Greenberg E; Preiss J (1965). "Biosynthesis of bacterial glycogen. II. Purification and properties of the adenosine diphosphoglucose:glycogen transglucosylase of arthrobacter species NRRL B1973". J. Biol. Chem. 240: 2341–2348. PMID 14304835.
Leloir LF, de Fekete MA, Cardini CE (1961). "Starch and oligosaccharide synthesis from uridine diphosphate glucose". J. Biol. Chem. 236: 636–641. PMID 13760681.
Whelan, W.J. and Schultz, J. (Eds.), Miami Winter Symposia, vol. 1, North Holland, Utrecht, 1970, p. 122-138.
starch, synthase, enzymology, starch, synthase, enzyme, that, catalyzes, chemical, reactionstarch, synthasecrystal, structure, glycogen, synthase, from, agrobacterium, tumefaciensidentifiersec, 21cas, 9030, 8databasesintenzintenz, viewbrendabrenda, entryexpasy. In enzymology a starch synthase EC 2 4 1 21 is an enzyme that catalyzes the chemical reactionstarch synthaseCrystal structure of glycogen synthase 1 from Agrobacterium tumefaciensIdentifiersEC no 2 4 1 21CAS no 9030 10 8DatabasesIntEnzIntEnz viewBRENDABRENDA entryExPASyNiceZyme viewKEGGKEGG entryMetaCycmetabolic pathwayPRIAMprofilePDB structuresRCSB PDB PDBe PDBsumGene OntologyAmiGO QuickGOSearchPMCarticlesPubMedarticlesNCBIproteins ADP glucose 1 4 alpha D glucosyl n displaystyle rightleftharpoons ADP 1 4 alpha D glucosyl n 1Thus the two substrates of this enzyme are ADP glucose and a chain of D glucose residues joined by 1 4 alpha glycosidic bonds whereas its two products are ADP and an elongated chain of glucose residues Plants use these enzymes in the biosynthesis of starch This enzyme belongs to the family of hexosyltransferases specifically the glycosyltransferases The systematic name of this enzyme class is ADP glucose 1 4 alpha D glucan 4 alpha D glucosyltransferase Other names in common use include ADP glucose starch glucosyltransferase adenosine diphosphate glucose starch glucosyltransferase adenosine diphosphoglucose starch glucosyltransferase ADP glucose starch synthase ADP glucose synthase ADP glucose transglucosylase ADP glucose starch glucosyltransferase ADPG starch synthetase and ADPG starch glucosyltransferaseFive isoforms seems to be present GBSS which is linked to amylose synthesis The others are SS1 SS2 SS3 and SS4 These have different roles in amylopectin synthesis New work implies that SS4 is important for granule initiation Szydlowski et al 2011 Structural studies editAs of late 2007 4 structures have been solved for this class of enzymes with PDB accession codes 1RZU 1RZV 2BFW and 2BIS References editChambers J Elbein AD 1970 Biosynthesis of glucans in mung bean seedlings Formation of beta 1 4 glucans from GDP glucose and beta 1 3 glucans from UDP glucose Arch Biochem Biophys 138 2 620 31 doi 10 1016 0003 9861 70 90389 9 PMID 4317490 FRYDMAN RB CARDINI CE 1965 Studies on adenosine diphosphate d glucose a 1 4 glucan a 4 glucosyltransferase of sweet corn endosperm Biochim Biophys Acta 96 2 294 303 doi 10 1016 0926 6593 65 90013 5 PMID 14298833 Greenberg E Preiss J 1965 Biosynthesis of bacterial glycogen II Purification and properties of the adenosine diphosphoglucose glycogen transglucosylase of arthrobacter species NRRL B1973 J Biol Chem 240 2341 2348 PMID 14304835 Leloir LF de Fekete MA Cardini CE 1961 Starch and oligosaccharide synthesis from uridine diphosphate glucose J Biol Chem 236 636 641 PMID 13760681 Whelan W J and Schultz J Eds Miami Winter Symposia vol 1 North Holland Utrecht 1970 p 122 138 Portal nbsp Biology This EC 2 4 enzyme related article is a stub You can help Wikipedia by expanding it vte Retrieved from https en wikipedia org w index php title Starch synthase amp oldid 1172361225, wikipedia, wiki, book, books, library,
