Lactate Assay - (Nov/24/2006 )

Hi,
I am looking for a colorimetric Lactate acid assay for cell cultures. Could someone help me with that?
Thanks in advance-

lactate can be measured by lactate dehydrogenase-catalyzed oxidation of lactate to pyruvate


LACTATE + NAD+ ------> PYRUVATE + NADH + H+


in a spectrophotometer you follow the reaction at 340 nm due to formation of NADH

as the reaction above is reversible you direct the reaction to the formation of pyruvate by adding hydrazine and further reaction to pyruvate hydrazone;

Thanks a lot, kosmodrom!