MetaCyc Enzyme: cytosolic 3-phosphoglycerate kinase

Synonyms: 3-PGKc, cytosolic 3-phosphoglycerate kinase

Species: Spinacia oleracea

A protein with 3-phoshoglycerate kinase activity was purified from a crude extract of spinach (Spinacia oleracea L.). In fact two isoforms of the protein were identified through this procedure: one is cytosolic (this protein), the other chloroplastic (see plastidic 3-phosphoglycerate kinase). The chloroplastic protein was also purified from isolated chloroplasts, allowing the exact determination of the identity of each crude extract-purified isoform [KopkeSecundo90]. The cytosolic protein has a molecular weight of 39 kDa by size exclusion chromatography (40.7 kDa on SDS-PAGE). The protein is monomeric. Its pH optimum is at 7.5 with a strong drop of activity at higher and lower pH values [KopkeSecundo90].

Locations: cytosol

Molecular Weight of Polypeptide: 39 kD (experimental) [KopkeSecundo90 ]

Gene-Reaction Schematic: ?

Gene-Reaction Schematic

GO Terms:

Cellular Component: GO:0005829 - cytosol [KopkeSecundo90]

Created 09-Nov-2006 by Tissier C , TAIR

Enzymatic reaction of: 3-phosphoglycerate kinase

EC Number:

3-phospho-D-glycerate + ATP <=> 1,3-bisphospho-D-glycerate + ADP

The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the direction in which it was curated.

This reaction is reversible.

In Pathways: superpathway of cytosolic glycolysis (plants), pyruvate dehydrogenase and TCA cycle , superpathway of anaerobic sucrose degradation , glycolysis IV (plant cytosol) , sucrose biosynthesis I (from photosynthesis)

The protein does not follow Michaelis-Menten kinetics for this reaction. The kinetics are biphasic and the enzyme exhibits 4-6 times higher affinity for the substrate in the lower concentration range than in the higher range [KopkeSecundo90].

Low concentration range: Km (MgATP) 240 μM, Km (3-PGA) 280 μM.

High concentration range: Km (MgATP) 1460 μM, Km (3-PGA) 1220 μM.

Inhibitors (Other): ATP [KopkeSecundo90]

Primary Physiological Regulators of Enzyme Activity: ATP

Kinetic Parameters:

Km (μM)

pH(opt): 7.5 [KopkeSecundo90]


KopkeSecundo90: Kopke-Secundo E., Molnar I., Schnarrenberger C. (1990). "Isolation and characterization of the cytosolic and chloroplastic 3-phosphoglycerate kinase from spinach leaves." Plant Physiol. 93:40-47.

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Please cite the following article in publications resulting from the use of MetaCyc: Caspi et al, Nucleic Acids Research 42:D459-D471 2014
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