Histidine

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l-Histidine

Skeletal formula of histidine (zwitterionic form)
Names
IUPAC name
Histidine
Other names
2-Amino-3-(1H-imidazol-4-yl)propanoic acid
Identifiers
3D model (
JSmol
)
84088
ChEBI
ChEMBL
ChemSpider
DrugBank
ECHA InfoCard
 100.000.678 Edit this at Wikidata
EC Number
  • 200-745-3
83042
IUPHAR/BPS
KEGG
UNII
  • 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 checkY
    Key: HNDVDQJCIGZPNO-YFKPBYRVSA-N checkY
  • O=C([C@H](CC1=CNC=N1)N)O
  • Zwitterion: O=C([C@H](CC1=CNC=N1)[NH3+])[O-]
  • Protonated zwitterion: O=C([C@H](CC1=CNC=[NH1+]1)[NH3+])[O-]
Properties
C6H9N3O2
Molar mass 155.157 g·mol−1
4.19g/100g @ 25 °C [1]
Hazards
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 1: Exposure would cause irritation but only minor residual injury. E.g. turpentineFlammability 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g. canola oilInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
1
1
0
Supplementary data page
Histidine (data page)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Histidine (symbol His or H)

protonated –NH3+ form under biological conditions), a carboxylic acid group (which is in the deprotonated –COO− form under biological conditions), and an imidazole side chain (which is partially protonated), classifying it as a positively charged amino acid at physiological pH. Initially thought essential only for infants, it has now been shown in longer-term studies to be essential for adults also.[3] It is encoded by the codons
CAU and CAC.

Histidine was first isolated by Albrecht Kossel and Sven Gustaf Hedin in 1896.[4] The name stems from its discovery in tissue, from ἱστός histós "tissue".[2] It is also a precursor to histamine, a vital inflammatory agent in immune responses. The acyl radical is histidyl.

Properties of the imidazole side chain

The conjugate acid (protonated form) of the

aromatic at all pH values.[8] Under certain conditions, all three ion-forming groups of histidine can be charged forming the histidinium cation.[9]

The acid-base properties of the imidazole side chain are relevant to the

haem
.

The tautomerism and acid-base properties of the imidazole side chain has been characterized by 15N NMR spectroscopy. The two 15N chemical shifts are similar (about 200 ppm, relative to

aromatic ring. At pH > 9, the chemical shifts of N1 and N3 are approximately 185 and 170 ppm.[11]

Ligand

electron transfer chain. The large semi-transparent sphere indicates the location of the iron ion. From PDB: 1YQ3
​.
The tricopper site found in many laccases, notice that each copper center is bound to the imidazole sidechains of histidine (color code: copper is brown, nitrogen is blue).

Histidine forms

complexes with many metal ions. The imidazole sidechain of the histidine residue commonly serves as a ligand in metalloproteins. One example is the axial base attached to Fe in myoglobin and hemoglobin. Poly-histidine tags (of six or more consecutive H residues) are utilized for protein purification by binding to columns with nickel or cobalt, with micromolar affinity.[12] Natural poly-histidine peptides, found in the venom of the viper Atheris squamigera have been shown to bind Zn(2+), Ni(2+) and Cu(2+) and affect the function of venom metalloproteases.[13]

Metabolism

Biosynthesis

Histidine Biosynthesis Pathway Eight different enzymes can catalyze ten reactions. In this image, His4 catalyzes four different reactions in the pathway.

l-Histidine is an essential amino acid that is not synthesized de novo in humans.[14] Humans and other animals must ingest histidine or histidine-containing proteins. The biosynthesis of histidine has been widely studied in prokaryotes such as E. coli. Histidine synthesis in E. coli involves eight gene products (His1, 2, 3, 4, 5, 6, 7, and 8) and it occurs in ten steps. This is possible because a single gene product has the ability to catalyze more than one reaction. For example, as shown in the pathway, His4 catalyzes 4 different steps in the pathway.[15]

Histidine is synthesized from

ribose-5-phosphate by ribose-phosphate diphosphokinase in the pentose phosphate pathway. The first reaction of histidine biosynthesis is the condensation of PRPP and adenosine triphosphate (ATP) by the enzyme ATP-phosphoribosyl transferase. ATP-phosphoribosyl transferase is indicated by His1 in the image.[15] His4 gene product then hydrolyzes the product of the condensation, phosphoribosyl-ATP, producing phosphoribosyl-AMP (PRAMP), which is an irreversible step. His4 then catalyzes the formation of phosphoribosylformiminoAICAR-phosphate, which is then converted to phosphoribulosylformimino-AICAR-P by the His6 gene product.[16] His7 splits phosphoribulosylformimino-AICAR-P to form d-erythro-imidazole-glycerol-phosphate. After, His3 forms imidazole acetol-phosphate releasing water. His5 then makes l-histidinol-phosphate, which is then hydrolyzed by His2 making histidinol. His4 catalyzes the oxidation of l-histidinol to form l-histidinal, an amino aldehyde. In the last step, l-histidinal is converted to l-histidine.[16][17]

The histidine biosynthesis pathway has been studied in the fungus Neurospora crassa, and a gene (His-3) encoding a multienzyme complex was found that was similar to the His4 gene of the bacterium E. coli.[18] A genetic study of N. crassa histidine mutants indicated that the individual activities of the multienzyme complex occur in discrete, contiguous sections of the His-3 genetic map, suggesting that the different activities of the multienzyme complex are encoded separately from each other.[18] However, mutants were also found that lacked all three activities simultaneously, suggesting that some mutations cause loss of function of the complex as a whole.

Just like animals and microorganisms, plants need histidine for their growth and development.[10] Microorganisms and plants are similar in that they can synthesize histidine.[19] Both synthesize histidine from the biochemical intermediate phosphoribosyl pyrophosphate. In general, the histidine biosynthesis is very similar in plants and microorganisms.[20]

Regulation of biosynthesis

This pathway requires energy in order to occur therefore, the presence of ATP activates the first enzyme of the pathway, ATP-phosphoribosyl transferase (shown as His1 in the image on the right). ATP-phosphoribosyl transferase is the rate determining enzyme, which is regulated through feedback inhibition meaning that it is inhibited in the presence of the product, histidine.[21]

Degradation

Histidine is one of the amino acids that can be converted to intermediates of the tricarboxylic acid (TCA) cycle (also known as the citric acid cycle).

tetrahydrofolate, and the remaining five carbons form glutamate.[22] Overall, these reactions result in the formation of glutamate and ammonia.[24] Glutamate can then be deaminated by glutamate dehydrogenase or transaminated to form α-ketoglutarate.[22]

Conversion to other biologically active amines
Conversion of histidine to histamine by histidine decarboxylase

Requirements

The

Recommended Dietary Allowances (RDAs) for essential amino acids in 2002. For histidine, for adults 19 years and older, 14 mg/kg body weight/day.[29] Supplemental histidine is being investigated for use in a variety of different conditions, including neurological disorders, atopic dermatitis, metabolic syndrome, diabetes, uraemic anaemia, ulcers, inflammatory bowel diseases, malignancies, and muscle performance during strenuous exercise.[30]

See also

References

  1. ^ http://prowl.rockefeller.edu/aainfo/solub.htm[full citation needed]
  2. ^ a b "Nomenclature and Symbolism for Amino Acids and Peptides". IUPAC-IUB Joint Commission on Biochemical Nomenclature. 1983. Archived from the original on 9 October 2008. Retrieved 5 March 2018.
  3. PMID 1123426
    .
  4. ISSN 0021-9258
    .
  5. ^
    PMID 23579613
    .
  6. ^ a b "HISTIDINE". ambermd.org. Retrieved 2022-05-12.
  7. ^
    S2CID 88813605
    .
  8. doi:10.1016/S0022-2860(03)00282-5
    .
  9. S2CID 265572280
    .
  10. ^
    PMID 22303266
    .
  11. ISBN 978-1-891389-18-4
    .
  12. PMID 11036646
    .
  13. PMID 26214303
    .
  14. ^ Roche Biochemical Pathways Map Roche biochemical pathways map
  15. ^
    PMID 8852895
    .
  16. ^
    PMID 23617600
    .
  17. PMID 13271397
    .
  18. ^ a b Ahmed A. Organization of the histidine-3 region of Neurospora. Mol Gen Genet. 1968;103(2):185-93. doi: 10.1007/BF00427145. PMID 4306011
  19. ^ "Understanding Genetics". genetics.thetech.org. Archived from the original on 2016-05-25. Retrieved 2016-05-19.
  20. S2CID 23733445
    .
  21. S2CID 18380727
    .
  22. ^ a b c Board review series (BRS)-- Biochemistry, Molecular Biology, and Genetics (fifth edition): Swanson, Kim, Glucksman
  23. PMID 4146796
    .
  24. PMID 13061415
    .
  25. PMID 26015312
    .
  26. ^ "3-Methylhistidine". HMDB Version 4.0. Human Metabolome Database. 20 December 2017. Retrieved 25 December 2017.
  27. S2CID 7661250
    .
  28. PMID 11544359
    .
  29. ISBN 978-0-309-08525-0
    .
  30. PMID 32235743
    .

External links
Retrieved from "https://en.wikipedia.org/w/index.php?title=Histidine&oldid=1214687997"