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

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

Prameter values

Parameter	Value	Organism	Remarks
$V_{mf}$	11.4	HeLa cell line
$V_{mr}$	1.8	Rat AS-30D hepatoma
$Km_{PYR}$	0.1
$Km_{LAC}$	4.7	Rat AS-30D hepatoma
$Km_{NAD}$	0.07
$Km_{NADH}$	0.002