Detailed introduction about l-Isoleucine

Posted by beauty33 on September 27th, 2021

Isoleucine is also known as \"Isoleucine\" and is named \"α-amino-β-methylvaleric acid\" systematically, and its chemical formula is C6H13NO2. It is one of the essential amino acids of the human body and a kind of neutral aliphatic amino acids. It is soluble in water and slightly soluble in ethanol.


Rhombus leaf-like or flaky crystals, bitter in taste. It is soluble in water and slightly soluble in ethanol.

Drug efficacy

The role of isoleucine includes working with leucine and valine to repair muscles, control blood sugar, and provide energy to body tissues. It also increases the production of growth hormone and helps to burn visceral fat, which is difficult to have an effective effect on them only through diet and exercise because it is inside the body. Leucine, isoleucine and valine are all branched-chain amino acids, which help promote muscle recovery after training. Among them, isoleucine is the most effective branched-chain amino acid, which can effectively prevent muscle loss because it can be broken down and converted into glucose more quickly. Increasing glucose can prevent muscle tissue damage, so it is particularly suitable for bodybuilders. Leucine also promotes the healing of bones, skin, and damaged muscle tissue. Doctors usually recommend that patients take leucine supplements after surgery.

Since it is easily converted into glucose, isoleucine helps regulate blood sugar levels. People with isoleucine deficiency will experience symptoms similar to hypoglycemia, such as headache, dizziness, fatigue, depression, confusion, and irritability.

The best food sources of isoleucine include brown rice, beans, meat, nuts, soy flour, and whole wheat. Since it is an essential amino acid, it means that the body cannot produce it on its own and can only be obtained through diet. People engaged in high-intensity physical activity and a low-protein diet should consider taking leucine supplements. Although there is a separate supplement form, it is best to take it with isoleucine and valine. Therefore, it is more convenient to choose mixed supplements.

But like anything, excessive intake of leucine can also cause side effects. Large intakes are known to be related to pellagra, vitamin A deficiency and other problems, and can cause dermatitis, diarrhea, mental disorders and other problems. Too much leucine in the diet can also increase the amount of ammonia in the body and destroy liver and kidney function. Therefore, patients with impaired liver or kidney function should not use large doses of leucine unless they have consulted with a doctor, as this will worsen the condition.

Test methods

Method name

Isoleucine crude drug—Determination of isoleucine—potentiometric titration

Scope of application

This method uses a titration method to determine the content of isoleucine in the isoleucine bulk drug.

This method is suitable for isoleucine bulk drugs.

Method principle

After the test product is dissolved in anhydrous formic acid, add glacial acetic acid to the potentiometric titration method, titrate with perchloric acid titrant, and calibrate the titration result with a blank test, and calculate the content of isoleucine based on the amount of titrant used.


1. Anhydrous formic acid

2. Glacial acetic acid

3. Perchloric acid titrant (0.1mol/L)

4. Crystal violet indicator solution

5. Benchmark potassium hydrogen phthalate

Equipment: Potentiometric Titrator

Sample preparation

1. Perchloric acid titrant (0.1mol/L)

Preparation: Take 750 mL of anhydrous glacial acetic acid (calculated based on the water content, add 5.22 mL of acetic anhydride per 1 g of water), add 8.5 mL of perchloric acid (70~72%), shake well, let cool, and add an appropriate amount of anhydrous glacial acetic acid to make Make 1000mL, shake well, and let stand for 24 hours. If the tested product is easily acetylated, the water content of the liquid must be determined by the moisture determination method, and then adjusted with water and acetic anhydride until the water content of the liquid is 0.01%~0.2%.

Calibration: Take about 0.16g of standard potassium hydrogen phthalate dried at 105? to constant weight, accurately weigh it, add 20mL of anhydrous glacial acetic acid to dissolve, add 1 drop of crystal violet indicator solution, and slowly titrate with this solution to Blue, and the titration result is corrected with a blank test. Each 1mL perchloric acid titrant (0.1mol/L) is equivalent to 20.42mg of potassium hydrogen phthalate. Calculate the concentration of the solution based on the consumption of the solution and the amount of potassium hydrogen phthalate taken.

2. Crystal Violet Indicator Solution

Take 0.5 g of crystal violet and add 100 mL of glacial acetic acid to dissolve.

Operation steps: Precisely weigh about 0.10g of the test sample, add 1mL of anhydrous formic acid to dissolve it, add 25mL of glacial acetic acid, and titrate with perchloric acid titrant (0.1mol/L) according to the potentiometric titration method, and the result of the titration Use blank test to correct. Each 1mL perchloric acid titrant (0.1mol/L) is equivalent to 13.12mg of C6H13NO2.

Note: \"Precision weighing\" means that the weighing should be accurate to one thousandth of the weighed weight. \"Precision measuring\" means that the accuracy of measuring the volume should meet the accuracy requirements of the volume pipette in the national standard.


The content is more in meat. There are 2 antipodal centers in isoleucine, so there are 4 stereoisomers and two diastereomers of L-isoleucine. L-isoleucine exists in various proteins, but in any case, there is only one type of isoleucine that naturally exists, that is, L-isoleucine. L-isoleucine is one of the essential amino acids, and it is nutritionally related to valine and leucine, which are similar in structure. Although it is a carbohydrate amino acid, it has a slight ketogenic effect. The α-methylbutyryl-CoA, which is produced from isoleucine by transamination and decarboxylation in the organism, undergoes similar decomposition of fatty acids to produce acetyl-CoA and propionyl-CoA. The latter becomes succinyl-CoA. Enter the citric acid cycle. When synthesized by bacteria, they are known to be composed of threonine and pyruvate dihydroxy acid → a-keto acid.

L-isoleucine is an essential amino acid for the human body and one of the three branched-chain amino acids. Because of its special structure and function, it occupies a particularly important position in human life metabolism. L-isoleucine is mainly used to prepare compound amino acid preparations, especially for high-branched chain amino acid infusion (such as 3H infusion, etc.) and oral liquid (ganan dry syrup, etc.).

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