What Is Isoleucine?
Isoleucine is an organic compound with the chemical formula C6H13NO2.
It is abbreviated as Ile (three letters) or I (one letter). It has a structure with a sec-butyl group on the side chain, and is classified as one of the branched-chain amino acids and a hydrophobic amino acid, and the L-body is used in most cases.
It has a molecular weight of 131.17, a melting point of 288°C (decomposition), and is a white crystal or crystalline powder at room temperature. It is odorless or has a slight odor, pH is 5.5-7.0 (1%, 20℃), and solubility in water is 4.02g/100g (20℃). It is insoluble in ethanol and insoluble in diethyl ether.
Uses of Isoleucine
Physiologically, isoleucine is classified as a type of essential amino acid that cannot be synthesized in the human body. Therefore, it is a substance that must normally be ingested from food and other sources. Major uses include pharmaceutical raw materials (e.g., infusions), culture media, and as an additive in foods and beverages. As a food additive, it is used to add flavor.
BCAAs are sometimes combined with valine and leucine to form BCAAs in supplements for muscle building. In synthetic chemistry, isoleucine is used in formulation research, amino acid research, and as an N-Fmoc protector in peptide synthesis.
Properties of Isoleucine
1. Isomers of Isoleucine
Isoleucine has four isomers: L-isoleucine, D-isoleucine, L-allo-isoleucine, and D-allo-isoleucine. Of these, L-isoleucine is the one used in nature, including in vivo. Synthetically, it is synthesized by a multi-step reaction using 2-bromobutane and diethyl malonate as starting materials.
2. Biosynthesis of Isoleucine
Isoleucine is not synthesized in the human body, but is biosynthesized in plants and microorganisms. 2-oxobutanoic acid is synthesized by various enzymes, and the specific synthetic pathways are as follows
- Dihydroxycarboxylic acids are produced by acetolactate synthase and ketolate reductoisomerase.
- Dihydroxyacid dehydratase converts it to α-ketocarboxylic acid by dehydration.
- Amino groups are transferred from glutamic acid by branched-chain amino acid aminase to form isoleucine.
3. Physiological Role of Isoleucine
Isoleucine is one of the essential amino acids in the human body. It helps strengthen muscles and relieve fatigue. For this reason, it is also called BCAA, along with the essential amino acids valine and leucine. It has also been shown to suppress elevated blood sugar levels, dilate blood vessels, and enhance liver function.
Types of Isoleucine
There are two main types of isoleucine available on the market today: industrial products and R&D products. Industrial products are often used in food additives and are generally offered in large quantities, such as 1 kg, 25 kg, and 50 kg. The main type of isoleucine sold is L isoleucine.
For research and development use, in addition to L isoleucine, racemic isoleucine is also sold as “DL-isoleucine. 5g, 10g, 25g, 50g, 100g, 500g, etc.” These are sold in small volumes that are easy to handle in the laboratory. Basically, these chemicals can be stored at room temperature. Also, for amino acid research and peptide synthesis, N-Fmoc protectors and other amino acid terminally protected products are available. These are basically reagents that are kept refrigerated or frozen.
Other products using isoleucine as an ingredient, such as supplements, are also widely available to the public.