Difference between revisions of "UDPG-pyrophosphorylase"

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This enzyme converts UTP and G1P to UDP-glucose (UDPG) and pyrophosphate (PPi)
 
This enzyme converts UTP and G1P to UDP-glucose (UDPG) and pyrophosphate (PPi)
  

Revision as of 16:49, 1 May 2014


This enzyme converts UTP and G1P to UDP-glucose (UDPG) and pyrophosphate (PPi)

Chemical equation

 UTP + Glc1P \rightarrow UDPG + PPi

Rate equation

Reversible Bi substrate Michaelis-Menten equation with random binding order is used [1]

 \frac{ \frac{V_{max}}{K_{UTP}K_{Glc1P}} \left( [UTP][Glc1P] - \frac{[UDPG][PPi]}{K_{eq}} \right)  }{ \left( 1 + \frac{[UTP]}{K_{UTP}} + \frac{[PPi]}{K_{PPi}} \right) \left( 1 + \frac{[UDPG]}{K_{UDPG}} + \frac{[Glc1P]}{K_{Glc1P}} \right)  }

Parameter values

Parameter Value Units Organism Remarks
V_{max} 200 [2] min^{-1} Recombinant, human muscle
K_{Glc1P} 0.4 [3] mM
K_{UTP} 0.92 [3] mM
K_{UDPG}  6.3 \times 10^{-2} [3] mM
K_{ppi} 0.38[3] mM
K_{eq} 0.24[3] Dimensionless

References

  1. Palm, D.C. (2013). The regulatory design of glycogen metabolism in mammalian skeletal muscle (Ph.D.). University of Stellenbosch
  2. Villar-Palasi C & Larner J (1960). Levels of activity of the enzymes of the glycogen cycle in rat tissues. Arch Biochem Biophys 86, 270–273.
  3. 3.0 3.1 3.2 3.3 3.4 Duggleby RG, Chao YC, Huang JG, Peng HL & Chang HY (1996). Sequence differences between human muscle and liver cDNAs for UDPglucose pyrophosphorylase and kinetic properties of the recombinant enzymes expressed in Escherichia coli. Eur J Biochem 235, 173–179.