Lactate dehydrogenase

A dehydrogenase is an enzyme that transfers a hydride from one molecule to another. Lactate dehydrogenase catalyzes the conversion of pyruvate to lactate and back, as it converts NADH to NAD⁺ and back.

Chemical reactions

$NADH + PYR \rightleftharpoons Lactate_{in} + NAD^+$

Rate equation

RAndom Bi-Bi reversible Michaelis-Menten equation is used.

$\frac{V_{mf}\frac{[NADH][PYR]}{Km_{NADH} K_{PYR}} - V_{mr}\frac{[Lactate_{in}][NAD]}{Km_{Lactate_{in}} K_{NAD}}}{1 + \frac{[NADH]}{Km_{NADH}} + \frac{[PYR]}{Km_{PYR}} + \frac{[NADH][PYR]}{Km_{NADH} Km_{PYR}} + \frac{[Lactate_{in}][NAD]}{Km_{Lactate_{in}} Km_{NAD}} + \frac{[Lactate_{in}]}{Km_{Lactate_{in}}} + \frac{[PYR]}{Km_{PYR}} }$

Prameter values

Parameter	Value	Units	Organism	Remarks
$V_{mf}$	741	$\text{mM min}^{-1}$	HeLa cell line
$V_{mr}$	117	$\text{mM min}^{-1}$	Rat AS-30D hepatoma
$Km_{PYR}$	0.1	mM	HeLa cell line
$Km_{LAC}$	4.7	mM	Rat AS-30D hepatoma
$Km_{NAD}$	0.07	mM	HeLa cell line
$Km_{NADH}$	0.002	mM	HeLa cell line