Lactate dehydrogenase catalyzes the last step of anaerobic glycolysis. In addition to the production of ATP glycolysis also yields the pyruvate and NADH. NADH is later used in the electron transport system for generating more ATP with enzymes located with membrane of the mitochondria. When Oxygen is absent, cells must go through fermentation. The purpose of this process is to get NAD. This NAD is recycled and without this step, glycolysis would not occur. Fermentation occurs in muscle fibers during exercise. Pyruvate is converted into lactic acid by way of reduced NADH. Lactate dehydrogenase catalyzes this reaction. There are multiple forms of lactate dehydrogenase found in different muscle tissues, these forms are called isozymes. These isozymes possess different structural properties but overall have the same function. The purpose of these isozymes is the allow for the adjustments needed in metabolism. Different tissues and organs have …show more content…
The isozymes of LDH in mammals differ in their respective amino acid sequences and their specific expression. LDH isozymes are expressed in two forms, M isozyme located in skeletal muscle (anerobic environment) and H isozyme located in heart muscle (aerobic environment). Both of which metabolize glucose but the heart muscle isozyme has a higher affinity for its substrates than skeletal muscle. Lactate dehydrogenase uses pyridine nucleotide coenzymes as cofactors to transfer H+. NAD+ is the oxidized form and NADH is the reduced form.
These nucleotides have differ in absorbance spectra. NAD+ has no absorbance and NADH is absorbed at 340nm. An experimental method that could be used to follow the rate of this reaction would require the use of a spectrophotometer due to NADH’s visible absorbance, allowing measurement