Histidine

• L-Histidine is a basic, genetically coded amino acid.
• It is a conditionally indispensable amino acid.

Symbol / Abbreviation

his

Molecular formula

C₆H₉N₃O₂

Structural formula

            H
            |
 HC===C-CH2-C-COOH
  |   |     |
  N   NH    NH2
  \\ /
   HC
 

Molecular weight

155.16

pK1 a-COOH	pK2 a-NH3	pKa R-group
1.8	9.3	6.0

Isoelectric point (pH)

7.47

CAS Registry Number

71-00-1