Appears as crystalline leaflets or a fine white crystalline powder possessing a distinct bitter taste. It dissolves in 25 parts of water, exhibits slight solubility in hot alcohol, and readily dissolves in both dilute mineral acids and alkaline solutions. Thermally, it undergoes sublimation at 168–170°C and melts with decomposition at approximately 284°C. A 1% aqueous solution exhibits a near-neutral to mildly acidic pH of 5.5 to 7.0. The absolute fraction, isolated via alcoholic extraction of the concrete with a 55–60% yield, presents as a semisolid, olive-green mass featuring a characteristic ambergris-like aromatic profile.
L-Isoleucine Chemical Properties
| Melting point | 288 °C (dec.) (lit.) |
| Alpha | 41 º (c=4, 6N HCl) |
| Boiling point | 225.8±23.0 °C(Predicted) |
| Bulk density | 470kg/m3 |
| Density | 1.2930 (estimate) |
| FEMA | 4675 | L-ISOLEUCINE |
| Refractive index | 40.5 ° (C=4, 6mol/L HCl) |
| Fp | 168-170°C |
| Storage temp | Store below +30°C |
| Solubility | 1 M HCl: 50 mg/mL |
| Form | powder |
| Pka | 2.32, 9.76(at 25℃) |
| Color | White to Off-white |
| Odor | odorless |
| PH | 5.5-6.5 (40g/l, H2O, 20℃) |
| Biological source | synthetic |
| Optical Rotation | [α]20/D +41.0±1°, c = 5% in 6 M HCl |
| Water Solubility | 41.2 g/L (50 ºC) |
| λmax | λ: 260 nm Amax: 0.07 λ: 280 nm Amax: 0.05 |
| JECFA Number | 2118 |
| Merck | 14,5179 |
| Sublimation | 168-170 ºC |
| BRN | 1721792 |
| InChIKey | AGPKZVBTJJNPAG-WHFBIAKZSA-N |
| LogP | 0.80 |
| CAS DataBase Reference | 73-32-5(CAS DataBase Reference) |
| NIST Chemistry Reference | Isoleucine(73-32-5) |
| EPA Substance Registry System | L-Isoleucine (73-32-5) |
Safety Information
| Hazard Codes | Xn |
| Risk Statements | 40 |
| Safety Statements | 24/25-36-22 |
| WGK Germany | 3 |
| RTECS | NR4705000 |
| TSCA | Yes |
| HS Code | 29224995 |
| Hazardous Substances Data | 73-32-5(Hazardous Substances Data) |
| Toxicity | LD50 intraperitoneal in rat: 6822mg/kg |
L-Isoleucine, also simply designated as isoleucine, is an essential branched-chain amino acid and a structural isomer of leucine. It plays a pivotal role in hemoglobin biosynthesis as well as in the physiological regulation of blood glucose and systemic energy homeostasis. Because the human body cannot synthesize L-Isoleucine de novo, it must be acquired through dietary sources to support physical endurance, muscle tissue repair, and post-exercise recovery. Consequently, it is widely utilized in sports nutrition and bodybuilding formulations to enhance stamina and accelerate muscle protein regeneration following strenuous resistance training.
