1 / 13

Serum Lactate dehydrogenase

Serum Lactate dehydrogenase. Description. Lactate dehydrogenase (NAD- dependent enzyme) belongs oxidoreductase class of enzymes acting on L-lactate (EC 1.1.1.27). Catalytic function of LDH.

meghan
Télécharger la présentation

Serum Lactate dehydrogenase

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Serum Lactate dehydrogenase

  2. Description Lactate dehydrogenase (NAD- dependent enzyme) belongs oxidoreductase class of enzymes acting on L-lactate (EC 1.1.1.27).

  3. Catalytic function of LDH • Lactate dehydrogenase catalyses the interconversion of pyruvate and lactate with concomitant interconversion of NADH and NAD+. • It converts pyruvate, the final product of glycolysis to lactate when oxygen is absent or in short supply. • It performs the reverse reaction during the cori cycle in the liver.

  4. Enzyme isoforms • LDH-1 (4H) - in the heart • LDH-2 (3H1M) - • LDH-3 (2H2M) - in the lungs • LDH-4 (1H3M) - in the kidneys • LDH-5 (4M) - in the liver and striated muscle

  5. The major isozymes of skeletal muscle and liver, M5, has four muscle (M) subunits; while H4 is the main isozymes for heart muscle. • Usually LDH-2 is the predominant form in the serum. • A LDH-1 level higher than the LDH-2 level , suggests myocardial infarction (damage to heart tissues releases heart LDH, which is rich in LDH-1, into the bloodstream.

  6. Diagnostic use Tissue breakdownelevates levels of LDH, and therefore a measure of it indicates: • Myocardial infarction:Significant elevation of LDH1 (LDH1LDH2). • Hemolysis: LDH is abundant in red blood cells. • Cancer:Predominant elevation of LDH2and LDH3occur in leukaemia.

  7. Lactate Dehydrogenase activity:is elevated in plasma following an infarction, peaking36 to40hours after the onset of symptoms remain elevated for up to 10 days. LDH activity is of diagnostic value in patients admitted morethan 48hours after the time when plasma CK2 may provide equivocal results. Normal range at 37°C 225-450 U/l

  8. Enzyme Activity AssaySpectrophotometry • Increase absorption of UV maximum at 340 nm.

  9. Separation of different LDH isoenzymes by electrophoresis • Serum LDH-isoenzyme patterns are determined by the agar gel electrophoretic and quantitative determination by densitometry.

  10. LDH1 is the fastest moving fraction towards the anode and LDH5 is the slowestmoving isoenzyme of LDH.

More Related