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Iodoacetamide

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Iodoacetamide
Skeletal formula
Space-filling model
Names
IUPAC name
Iodoacetamide
Identifiers
3D model (JSmol)
ChEMBL
ChemSpider
ECHA InfoCard 100.005.119 Edit this at Wikidata
EC Number
  • 205-630-1
RTECS number
  • AC4200000
UNII
  • InChI=1S/C2H4INO/c3-1-2(4)5/h1H2,(H2,4,5) checkY
    Key: PGLTVOMIXTUURA-UHFFFAOYSA-N checkY
  • InChI=1/C2H4INO/c3-1-2(4)5/h1H2,(H2,4,5)
    Key: PGLTVOMIXTUURA-UHFFFAOYAE
  • C(C(=O)N)I
Properties
C2H4INO
Molar mass 184.964 g·mol−1
Appearance Yellow-brown crystals
Melting point 94 °C (201 °F; 367 K)
Hazards
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 3: Short exposure could cause serious temporary or residual injury. E.g. chlorine gasFlammability 0: Will not burn. E.g. waterInstability 1: Normally stable, but can become unstable at elevated temperatures and pressures. E.g. calciumSpecial hazards (white): no code
3
0
1
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
checkY verify (what is checkY☒N ?)

2-Iodoacetamide is an alkylating agent used for peptide mapping purposes. Its actions are similar to those of iodoacetate. It is commonly used to bind covalently with the thiol group of cysteine so the protein cannot form disulfide bonds.[1][2] Also used in ubiquitin studies as an inhibitor of deubiquitinase enzymes (DUBs) because it alkylates the cysteine residues at the DUB active site. Like many other alkylating agents, iodoacetamide is highly toxic. In laboratory mice it has been shown to cause skin tumors and negatively affect reproductive ability. It may act as a human carcinogen, and may cause reproductive damage.[citation needed]

Peptidase inhibitor

Iodoacetamide is an irreversible inhibitor of all cysteine peptidases, with the mechanism of inhibition occurring from alkylation of the catalytic cysteine residue (see schematic). In comparison with its acid derivative, iodoacetate, iodoacetamide reacts substantially more slowly. This observation appears contradictory to standard chemical reactivity, however the presence of a favourable interaction between the positive imidazolium ion of the catalytic histidine and the negatively charged carboxyl-group of the iodoacetate is the reason for the increased relative activity of iodoacetamide.[3]

Mechanism of irreversible inhibition of cysteine peptidases with iodoacetamide.

References

  1. ^ Smythe CV (1936). "The reactions of Iodoacetate and of Iodoacetamide with various Sulfhydryl groups, with Urease, and with Yeast preparations". J. Biol. Chem. 114 (3): 601–12.
  2. ^ Anson ML (1940). "The reactions of Iodine and Iodoacetamide with native Egg Albumin". J. Gen. Physiol. 23 (3): 321–31. doi:10.1085/jgp.23.3.321. PMC 2237930. PMID 19873158.
  3. ^ Polgar, L (1979). "Deuterium isotope effects on papain acylation. Evidence for lack of general base catalysis and for enzyme-leaving group. interaction". Eur. J. Biochem. 98 (2): 369–374. doi:10.1111/j.1432-1033.1979.tb13196.x. PMID 488108.