Histidine

INTRODUCTION:
  • Histidine is both an essential amino acid and non-essential amino acid, has as a positively charged imidazole functional group.
  • Alpha amino acid
  • Amino acids with extra NH; (amino group) in strucuture
  • The imidazole makes it a common participant in enzyme catalyzed reactions.
  • The unprotonated imidazole is nucleophilic and can serve as a general base, while the protonated form can serve as a general acid. 
  • The residue can also serve a role in stabilizing the folded structures of proteins.
  • Amino acid with dissociation constant closest to physiological pH
  • Maximum influence of local milieu on ionization is on Histidine
  • Histidine is a semiessential basic amino acid
  • Aminoacids with its PKR value within physiological range is Histidine
  • FIGLU is a metabolite of Histidine
FUNCTIONS:
  • It develop and maintain healthy tissues in all parts of the body, particularly the myelin sheaths that coat nerve cells and ensure the transmission of messages from the brain to various parts of the body. 
  • It may be useful for treatment of mental disorders as well as certain types of sexual dysfunction.
  • Histidine is most responsible for the buffering capacity of hemoglobin and other proteins
  • Histidine levels in the body must be balanced to ensure good mental and physical health.
  • Histidine is important to normal sexual functioning, because it gets converted into histamine, a chemical needed to stimulate sexual arousal.
  • Histamine is also needed to help the immune system know when the body is experiencing an allergic reaction, and for the production of gastric juices needed for normal
  • digestion.
  • Histidine also acts as a natural detoxifier, protecting against radiation damage, and removing heavy metals from the system. 
  • It may even help prevent the onset of AIDS— Histidine is crucial to the production of both red and white blood cells. 
  • Histidine on decarboxylation produces histamine a potent vasodilator
  • Histidine can protonate & deprotonate at neutral pH
IMPORTANCE:
  • Histidine facilitates the growth and repair of all body tissue.
  • It manufactures white and red blood cells.
  • It is key in the manufacture and maintenance of oligo-dendrocytes that wrap around nerves forming myelin, a protective sheath, thus preventing unintended impulses that lead to spinal cord and brain defects.
  • Histidine removes heavy metals and protects from radiation. It aids in digestion by producing gastric juices.
  • The amino acid which on decarboxylation gives rise to a product with potent vasodilator properties is Histidine 
SOURCES:
  •    Histidine is found in many high-protein foods, such as meat and dairy products, as well as grains such as rice, wheat, and rye. It is not certain if histidine is an essential or non-essential amino acid
Exam Question
  • Haemoglobin synthesis starts with Histidine
  • Histidine is a polar amino acids
  • Aminoacids with its PKR value within physiological range is Histidine
  • FIGLU is a metabolite of Histidine
  • Histidine is most responsible for the buffering capacity of hemoglobin and other proteins
  • Amino acid with dissociation constant closest to physiological pH
  • The amino acid which on decarboxylation gives rise to a product with potent vasodilator properties is Histidine 
  • Histidine is is heterocyclic in structure
  • Histidine is a semiessential basic amino acid
  • Maximum influence of local milieu on ionization is on Histidine
  • Histidine can protonate & deprotonate at neutral pH
  • Amino acids with extra NH; (amino group) in strucuture
Don't Forget to Solve all the previous Year Question asked on Histidine