What is Histidine?

Histidine is an essential amino acid that plays a vital role in the biosynthesis of proteins. It comprises a carboxylic acid group, α-amino group, and an imidazole side chain thus labeling it into a positively charged amino acids in terms of physiological pH.


Histidine Structure

Chemical Properties of Histidine 

Histidine is evident as it comprises of the ring structure in its ‘R’ group consisting of 2 nitrogen group.
Chemical Structure: C6H9N3O2 
Abbreviation used to represent this essential amino acid is either ‘His’ or ‘H’. They are generally positively charged.

Biochemistry  Imidazole chain is an element of catalytic sites found in certain enzymes and it is one of the most prevalent coordinating ligands in metalloproteins. In Order to activate it as a nucleophile in catalytic triads, basic nitrogen of histidine are used to abstract a proton from a cysteine, threonine, and serine. Whereas in the case of a proton shuttle, it is used to shuttle protons.

Aromaticity At each level of ph value, imidazole ring of histidine is aromatic. It comprises of 6 pi electrons among which 2 form a nitrogen lone pair and four form 2 double bonds.  It can possibly lead to the formation of pi-stacking interactions but it is hard due to positive charges.

Benefits of Histidine 

  • L-Histidine is a vital amino acid that is needed by the body mainly in the growing stage of the children. Hence, it is present in means of supplementary or in food.
  • Various food products that include histidine are fish, meat and dairy products.
  • It is helpful in transferring a large amount of iron and copper.
  • It controls diarrhea as it boosts absorption of calcium thus decreasing the histidine level. But excessive consumption would lead to some side effects such as constipation.
  • It has a symbolic mechanism in preventing internal bleeding and clotting of blood.

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Practise This Question

Nonmetals are electronegative. They tend to form bonds by losing electrons.