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Parallel enzymatic and non-enzymatic formation of zinc protoporphyrin IX in pork

Miquel Becker, E.; Westermann, S.; Hansson, Mats LU and Skibsted, L. H. (2012) In Food Chemistry 130(4). p.832-840
Abstract
Zinc protoporphyrin is formed in pork homogenates in both enzymatic and non-enzymatic reactions. Ferrochelatase is active in formation of the highly fluorescent pigment known from Parma ham as demonstrated by inhibition with N-methylmesoporphyrin and by thermal inactivation. A non-enzymatic transmetallisation reaction, exchange of iron in myoglobin by zinc(II), is demonstrated by Pb(II) inhibition of zinc protoporphyrin formation at low Pb(II) concentrations, but promoted at higher Pb(II) concentrations. The non-enzymatic reaction is characterised as a slow bimolecular reaction between protoporphyrin IX and zinc(II) with a second-order rate constant of 0.63 I mol(-1) s(-1) at 35 degrees C and a high energy of activation of 98 kJ mol(-1)... (More)
Zinc protoporphyrin is formed in pork homogenates in both enzymatic and non-enzymatic reactions. Ferrochelatase is active in formation of the highly fluorescent pigment known from Parma ham as demonstrated by inhibition with N-methylmesoporphyrin and by thermal inactivation. A non-enzymatic transmetallisation reaction, exchange of iron in myoglobin by zinc(II), is demonstrated by Pb(II) inhibition of zinc protoporphyrin formation at low Pb(II) concentrations, but promoted at higher Pb(II) concentrations. The non-enzymatic reaction is characterised as a slow bimolecular reaction between protoporphyrin IX and zinc(II) with a second-order rate constant of 0.63 I mol(-1) s(-1) at 35 degrees C and a high energy of activation of 98 kJ mol(-1) for acetone:water (3:1, v/v) as solvent. Zinc protoporphyrin formation is concluded to be thermodynamically controlled with a formation constant of 4 x 10(5) M (35 degrees C, acetone:water (3:1)). An efficient inhibition of formation of zinc protoporphyrin by nitrite is related to myoglobin as substrate and involves both enzymatic and non-enzymatic reactions. (Less)
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author
publishing date
type
Contribution to journal
publication status
published
subject
in
Food Chemistry
volume
130
issue
4
pages
832 - 840
publisher
Elsevier
external identifiers
  • scopus:80052964604
ISSN
1873-7072
DOI
10.1016/j.foodchem.2011.07.090
language
English
LU publication?
no
id
20e590c6-d508-410b-848f-c23fd43ed3c4 (old id 8001626)
date added to LUP
2015-09-30 14:08:04
date last changed
2017-07-23 04:20:55
@article{20e590c6-d508-410b-848f-c23fd43ed3c4,
  abstract     = {Zinc protoporphyrin is formed in pork homogenates in both enzymatic and non-enzymatic reactions. Ferrochelatase is active in formation of the highly fluorescent pigment known from Parma ham as demonstrated by inhibition with N-methylmesoporphyrin and by thermal inactivation. A non-enzymatic transmetallisation reaction, exchange of iron in myoglobin by zinc(II), is demonstrated by Pb(II) inhibition of zinc protoporphyrin formation at low Pb(II) concentrations, but promoted at higher Pb(II) concentrations. The non-enzymatic reaction is characterised as a slow bimolecular reaction between protoporphyrin IX and zinc(II) with a second-order rate constant of 0.63 I mol(-1) s(-1) at 35 degrees C and a high energy of activation of 98 kJ mol(-1) for acetone:water (3:1, v/v) as solvent. Zinc protoporphyrin formation is concluded to be thermodynamically controlled with a formation constant of 4 x 10(5) M (35 degrees C, acetone:water (3:1)). An efficient inhibition of formation of zinc protoporphyrin by nitrite is related to myoglobin as substrate and involves both enzymatic and non-enzymatic reactions.},
  author       = {Miquel Becker, E. and Westermann, S. and Hansson, Mats and Skibsted, L. H.},
  issn         = {1873-7072},
  language     = {eng},
  number       = {4},
  pages        = {832--840},
  publisher    = {Elsevier},
  series       = {Food Chemistry},
  title        = {Parallel enzymatic and non-enzymatic formation of zinc protoporphyrin IX in pork},
  url          = {http://dx.doi.org/10.1016/j.foodchem.2011.07.090},
  volume       = {130},
  year         = {2012},
}