L-Isoleucine

L-Isoleucine, CAS 73-32-5, molecular formula C6H13NO2, molecular weight 131.17, is an essential branched-chain amino acid and a structural isomer of leucine, differing in the position of the methyl branch. It carries two chiral centres, which is why identity control rests heavily on optical rotation: the USP range of +38.9° to +41.8°, measured at 4% in 6 N hydrochloric acid, is markedly higher than that of either leucine or valine and is the quickest compendial discriminator between the three. Thovek supplies fermentation-derived material of non-animal origin, recovered by ion exchange and crystallisation from plant-derived carbohydrate feedstock. Compendial grade is available against USP, Ph. Eur./BP, JP and FCC. USP requires an assay of 98.5-101.5% on the dried basis, pH 5.5 to 7.0 in a 1 in 100 solution, loss on drying and residue on ignition each not more than 0.30%, chloride not more than 0.05%, sulphate not more than 0.03% and iron not more than 30 ppm; European and Japanese texts state 98.5-101.0% on the dried substance. Because isoleucine, leucine and valine co-elute closely, related-substance control is the critical release test: manufacturer grades typically hold leucine at not more than 0.30% with total impurities at not more than 1.00%, alongside ammonium not more than 0.02%, heavy metals not more than 10 ppm as Pb and arsenic not more than 1 ppm. Elemental impurities are reported against ICH Q3D, and endotoxin and microbiological data are supplied where the end use requires them. Isoleucine is sparingly soluble in water, dissolving to roughly 34 g/L at 25 °C, and is normally used as the single part in the 2:1:1 branched-chain blend rather than on its own. Typical destinations are BCAA and EAA powders, sports and recovery formats, clinical and parenteral nutrition, protein fortification of beverages and bars, cell-culture and fermentation media, and animal nutrition. Shipments are packed in 25 kg net bags with a food-grade inner liner and released with a full certificate of analysis, safety data sheet and non-GMO, allergen, BSE/TSE-free, halal and kosher statements.