Literature summary extracted from

Edwards, A.; Borthakur, A.; Bornemann, S.; Venail, J.; Denyer, K.; Waite, D.; Fulton, D.; Smith, A.; Martin, C.
Specificity of starch synthase isoforms from potato (1999), Eur. J. Biochem., 266, 724-736.

Activating Compound

EC Number	Activating Compound	Comment	Organism	Structure
2.4.1.21	amylopectin	50 mg/ml, 6fold activation of granule-bound starch synthase I	Solanum tuberosum
2.4.1.21	citrate	500 mM, 9.3fold activation of granule-bound starch synthase I, 1.8 fold activation of starch synthase II	Solanum tuberosum

Cloned(Commentary)

EC Number	Cloned (Comment)	Organism
2.4.1.21	expression of granule-bound starch synthase I and soluble starch synthase II in Escherichia coli	Solanum tuberosum

KM Value [mM]

EC Number	KM Value [mM]	KM Value Maximum [mM]	Substrate	Comment	Organism	Structure
2.4.1.21	additional information	-	additional information	granule-bound starch synthase I, amylpectin: 10 mg/ml, starch synthase II, amylopectin: 0.79 mg/ml	Solanum tuberosum
2.4.1.21	0.07	-	ADPglucose	starch synthase II, 5 mg/ml amylopectin	Solanum tuberosum
2.4.1.21	1.3	-	ADPglucose	granule bound starch synthase I, 5 mg/ml amylopectin	Solanum tuberosum

Organism

EC Number	Organism	UniProt	Comment	Textmining
2.4.1.21	Solanum tuberosum	-	-	-

Substrates and Products (Substrate)

EC Number	Substrates	Comment Substrates	Organism	Products	Comment (Products)	Rev.	Reac.
2.4.1.21	ADP-glucose + maltotriose	-	Solanum tuberosum	ADP + maltotetraose	granule-bound starch synthase I synthesizes maltotetraose and several higher maltose-oligosaccharides	?
2.4.1.21	ADP-glucose + maltotriose	-	Solanum tuberosum	ADP + maltotetraose	starch synthase II adds only 1 glucose unit to the primer	?

Temperature Stability [°C]

EC Number	Temperature Stability Minimum [°C]	Temperature Stability Maximum [°C]	Comment	Organism
2.4.1.21	25	-	granule-bound starch synthase I, loss of 35% activity after 1 h	Solanum tuberosum
2.4.1.21	35	-	starch synthase II, loss of 6% activity after 1 h	Solanum tuberosum
2.4.1.21	40	-	granule-bound starch synthase I, complete inactivation after 1 h, starch synthase II, loss of 52% activity after 1 h	Solanum tuberosum

Use of this online version of BRENDA is free under the CC BY 4.0 license. See terms of use for full details.

Release 2023.1 (January 2023)