L-Histidine

Catalog	BBC71001
CAS	71-00-1
Structure
Description	Histidine (abbreviated as His or H; encoded by the codons CAU and CAC) is an α-amino acid that is used in the biosynthesis of proteins. It contains an α-amino group (which is in the protonated –NH3+ form under biological conditions), a carboxylic acid group (which is in the deprotonated –COO− form under biological conditions), and a side chain imidazole, classifying it as a positively charged amino acid at physiological pH. Initially thought essential only for infants, longer-term studies have shown it is essential for adults also.Histidine was first isolated by German physician Albrecht Kossel and Sven Hedin in 1896. It is also a precursor to histamine, a vital inflammatory agent in immune responses. The acyl radical is histidyl.
Synonyms	4-(2-Amino-2-carboxyethyl)imidazole
IUPAC Name	(2S)-2-Amino-3-(1H-imidazol-5-yl)propanoic acid
Molecular Weight	155.15
Molecular Formula	C6H9N3O2
Canonical SMILES	C1=C(NC=N1)CC(C(=O)O)N
InChI	InChI=1S/C6H9N3O2/c7-5(6(10)11)1-4-2-8-3-9-4/h2-3,5H,1,7H2,(H,8,9)(H,10,11)/t5-/m0/s1
InChI Key	HNDVDQJCIGZPNO-YFKPBYRVSA-N
Boiling Point	278.95 °C
Melting Point	282 °C(lit.)
Flash Point	282ºC
Purity	99%
Density	1.3092 g/cm³
Solubility	Soluble in water, insoluble in ether
Appearance	Solid
Storage	2-8 °C
Active Content	95%
EC Number	225-660-9
pH	7-8.5
pKa	1.8(at 25 °C)
Refractive Index	1.731
Solubility in Water	41.6 g/L (25 ºC)