What Causes the Production Of Lactic Acid?

Lactic acid (IUPAC scientific name: 2-hydroxypropionic acid) is a compound that functions in a variety of biochemical processes. It is a carboxylic acid with a molecular formula of C ₃ H ₆ O ₃ . It is a carboxylic acid containing a hydroxyl group and is therefore an alpha-hydroxy acid (AHA). In aqueous solution, its carboxyl group releases a proton, which generates lactate ion CH ₃ CHOHCOO . Lactate dehydrogenase converts pyruvate to L-lactic acid during fermentation. Lactic acid is constantly produced during normal metabolism and exercise, but its concentration does not generally rise. ^[1]

During fermentation

Name: Lactic acid

English name: Lactic acid; 2-Hydroxy propionic acid

Other names: 2-hydroxypropionic acid; -hydroxypropionic acid; propanoic acid

CAS number: 50-21-5

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Method name: Determination of lactic acid-neutralization titration

Application range: This method uses the titration method to determine the content of lactic acid (C ₃ H ₆ O ₃ ).

This method is applicable to lactic acid.

Principle of the method: After the test sample is dissolved in water, 25 mL of sodium hydroxide titration solution (1 mol / L) is precisely added, and the solution is boiled for 5 minutes. Two drops of phenolphthalein indicator solution are added. Titrate with sulfuric acid titration solution (0.5 mol / L) while hot. And the result of the titration is corrected by a blank test. When the phenolphthalein indicator solution turns red, the titration is stopped. The amount of sulfuric acid titrant used is read out to calculate the lactic acid content.

Reagent: 1. Water (new boiling to room temperature)

2. Sodium hydroxide titration solution (1mol / L)

3. Sulfuric acid titration solution (0.5mol / L)

4. Phenolphthalein indicator liquid

5.

Pure

For the human body, lactic acid is one of the fatigue substances.

The human body needs a lot of energy during intense exercise. At this time, the production of lactic acid in the human body is faster than the removal of lactic acid by the tissue, and the lactic acid concentration in the tissue increases. The significance of this process is to rebuild the nicotinyl adenine dinucleotide (NAD) required for glycolysis to maintain adenosine triphosphate production and increase a steady stream of energy for exercise. This process can be described as ^[5] :

Pyruvate + NADH + H ⁺ Lactic acid + NAD ⁺

Unlike the general misrepresentation that an increase in lactic acid concentration itself does not cause acidosis, it is not the cause of muscle soreness. Lactic acid does not release protons in the body and is therefore not acidic. Analysis of the glycolytic pathway in the human body proves that this process does not cause acidosis. There is another cause of acidosis caused by intense exercise.

The energy released when adenosine triphosphate is split is that it releases a proton. These protons are the cause of acidosis. Aerobic metabolism cannot guarantee the production of adenosine triphosphate during intense exercise, so anaerobic metabolism begins. This process can produce a large number of adenosine triphosphates. These adenosine triphosphates release a large number of protons during decomposition, lowering the pH value in the tissue, causing acidosis. This is one of the many causes of muscle soreness during intense exercise. Some people think that lactic acid can cause acidosis through a strong ion concentration gradient, but the research on this process is very imperfect, so it is unclear whether it exists.