L-HISTIDINE MONOHYDROCHLORIDE MONOHYDRATE and L-HISTIDINE are hydrophilic essential amino acids that has a basic side-chain containing an imidazole group. It is biosynthesized from ATP, 5-phosphoribosyl-1-pyrophosphate (PRPP) and glutamine. This essential amino acid can be degraded to glutamate by histidiase, urocanase and imidazolonepropionase, and is the precursor of histamine by action of histidine decarboxylase.
L-Histidine has been used in cultures of many cells. Exogenous histidine has been shown to enhance the biosynthesis of lovastatin by cultured Aspergillus terreus. Histidine has been utilized as a single nitrogen source to probe swarming in Pseudomonas aeruginosa on agar.