Histidine stands out among amino acids because of its unique imidazole side chain, which gives it both fundamental importance in biology and practical use in research, pharmaceuticals, and nutrition fields. As an essential amino acid, the human body cannot manufacture it internally but draws it from diet and raw material sources. Its chemical formula is C6H9N3O2, and its molecular weight clocks in at 155.15 g/mol. Histidine’s layout makes it a key player in protein synthesis, acid-base regulation, metal ion binding, enzyme catalysis, and immune responses. Its HS Code typically falls under 2922.50, recognized internationally for trade and transportation of histidine as a chemical raw material.
Holding a white to off-white color, histidine presents as a solid—often appearing in its crystalline, flake, powder, pearl, or granular form, depending on manufacturing and refinement process. This substance rarely shows up as a liquid under standard temperature and pressure, due to its sturdy molecular interactions. In crystalline form, histidine produces a structure marked by needle-shaped or plate-like crystals, prized for their stability. Its melting point sits at around 287°C, and it decomposes before reaching true melting in air. Histidine’s density measures up at about 1.6 g/cm3, a testament to its compact packing. The solubility in water rises above 40 mg/mL at room temperature, which aids in its utility for making buffer solutions or analogues for laboratory work. The imidazole ring holds a pKa near 6.0, letting it easily accept or donate a hydrogen ion—this property lets histidine act as an effective buffer in biochemistry settings, especially where small changes in pH delicate processes.
Histidine’s formula, C6H9N3O2, marks it as a heterocyclic amino acid, a chemical term hinting at its function-rich side chain. The imidazole ring at its core puts it in a league of its own among amino acids, creating a molecular environment both polar and basic. The presence of a carboxyl group (COOH), an amino group (NH2), and that imidazole ring all on one chain make histidine flexible and reactive in both acid and base contexts. With substantial hydrogen bonding potential and strong chelating ability, this material regularly shows up as a ligand for transition metals like copper and zinc, vital in countless metalloproteins. Chemical suppliers ship histidine in solid forms like powder, flakes, or crystals because these formats store well, resist clumping, and measure out easily for processing or solution preparation.
Pharmaceutical-grade histidine, often stored as a pure white or off-white crystalline powder, comes in bulk packaging for manufacturers or research labs. Typical purity exceeds 98%, with moisture content held well below 1% to prevent degradation. Safe handling emerges as a priority, particularly for personnel weighing or mixing raw powder; the dust can irritate mucous membranes or lungs if inhaled, even though histidine itself rarely classifies as hazardous or acutely harmful per GHS standards. Since histidine is vital for infant and childhood growth, medical nutrition products and parenteral formulations count on a reliable supply. In cell culture, it appears in controlled, sterile solutions, often measured by liter with tight controls on pH, density, and solute concentration. Its strong buffering action reveals itself in enzyme studies or when stabilizing proteins for storage or crystallization.
While histidine generally falls under the category of safe raw materials, responsible storage and handling remain critical in facilities that process large amounts. Powder form demands proper dust control to avoid respiratory exposure or slip hazards on floors. Containers, whether lined drums or heavy-duty plastic bags, need sealing to prevent moisture uptake and contamination. Histidine solutions, prepared for laboratory analyses or medical products, warrant labeling for chemical identity, concentration, and pH to avoid accidental misuse. This material does not typically pose environmental danger, but keeping it out of water systems or storm drains avoids unnecessary stress on aquatic life.
With the global demand for reliable raw materials, histidine has earned a fixed position in manufacturing and research centers alike. The simplicity in its molecular structure belies its broad versatility. Its buffering power, chelation capacity, and building block status for advanced chemicals or drugs make it indispensable in vaccines, biotech processes, and nutritional products. Agents in trade and supply chain management, who oversee logistics for histidine under HS Code 2922.50, work to align purity levels, physical properties, and packaging with end-user needs. In facilities where damage from hazardous chemicals is a concern, histidine delivers a low-risk alternative for buffer preparation and protein stabilization compared to strong acids or bases. For specialists who need a material that delivers reliability in both solid and solution form, histidine’s unique physical and chemical profile keeps it in demand.
