UDPG-pyrophosphorylase

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

Chemical equation

UTP + Glc1P \rightarrow UDPG + PPi

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	Value	Organism	Remarks
$V_{max}$	200 ^[2]	HeLa cell line	Recombinant, human muscle
$K_{Glc1P}$	0.4 ^[3]	Recombinant, human muscle
$K_{UTP}$	0.92 ^[3]	Recombinant, human muscle
$K_{UDPG}$	$6.3 \times 10^{-2}$ ^[3]	Recombinant, human muscle
$K_{ppi}$	$0.38$ ^[3]	Recombinant, human muscle
$Keq$	0.24 <ref name="bergamini_1983">Bergamini C, Signorini M, Ferrari C & Dallocchio F (1983) Non-Michaelian kinetics of rabbit muscle uridine diphosphoglucose pyrophosphorylase. ArchBiochem Biophys 227, 397–405.

↑ Palm, D.C. (2013). The regulatory design of glycogen metabolism in mammalian skeletal muscle (Ph.D.). University of Stellenbosch
↑ 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.
↑ ^3.0 ^3.1 ^3.2 ^3.3 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.