Both assays are accepted reference methods for measurement of lactate dehydrogenase (LDH) activity (2-4). At pH 7.4, pyruvate -* lactate (P -* L) activity is about three times lactate -+ pyruvate (L P) activity, because equilibrium favors formation of lactate. Normal range for the P -* L assay is 130-265 spectrophotometric units at 25#{176} (3); normal range for the L P assay is 40-98 units at ...

Serum LDH activities assayed spectrophotometrically by the “forward” (lactate + DPN to pyruvate + DPNH + H) method have linear reaction rates, activity proportional to the amount of serumadded,anda reproducibilityof 1.3%. The reagent mixtore can be stored frozen for 6 monthsand in the lyophilized state indefinitely. Poor separationof normal from abnormal serum LDH activities results from the no...

A rapid and sensitive spectrophotometric assay for venom phospholipase A2 based on the hemolysis of guinea pig erythrocytes in the presence of decomplemented serum and cardiotoxin (direct lytic factor) is described. This assay is particularly useful for rapid multisample analyses, such as those used in monitoring chromatography fractions, and is specific for phospholipase A2 in the presence of ...