Pyrophosphate phosphohydrolase

Pyrophosphate phosphohydrolase that catalyze the reaction that converts Pyrophosphate into two molecules of Phosphate.

Chemical equation

$PPi \rightarrow 2 Pi$

Rate equation

Simple Michaelis-Menten rate law is used for this reaction

$\frac{V_{max[PP]}}{[PP] + K_{m}^{PP}}$

Parameter values

• A mean body weight is defined as 75Kg in Konig et. al . The $V_{max}$ is calculated by multiplying the reported value with body weight.

Parameter	Value	Units	Organism	Remarks
$V_{max}$	$0.36$	$mM/min^{-1}$	Human Liver
$K_{m}^{PPi}$	$0.96$	mM	Human cancer

Parameters with uncertainty

• The minimum and maximum value for $K_{m}^{PPi}$ has been reported to be 0.25 and 1.67. Calculating the mean and Std. Dev. using the range formula gives a value of $0.96 \pm 0.35$ for this parameter.

Parameter	Value	Units	Organism	Remarks
$V_{max}$	$0.36$	$mM/min^{-1}$	Human Liver
$K_{m}^{PPi}$	$0.96 \pm 0.35$	mM	Rat liver