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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1977-10-20
pubmed:abstractText
The heme vicinities of the acid and alkaline forms of native (Fd(III)) horseradish peroxidase were investigated in terms of the magnetic circular dichroism (MCD) spectroscopy. The MCD spectrum of the acid form of native horseradish peroxidase was characteristic of a ferric high spin heme group. The resemblance in the MCD spectrum between the acid form and acetato-iron (III)protoporphyrin IX dimethyl ester suggests that the heme iron of the acid form has the electronic structure similar to that in a pentocoordinated heme complex. The MCD spectra of native horseradish peroxidase did not shown any substantial pH dependence in the pH range from 5.20 to 9.00. The MCD spectral change indicated the pK value for the equilibrium between the acid and alkaline forms to be 11.0 which agrees with the results from other methods. The alkaline form of native horseradish peroxidase at pH 12.01 exhibited the MCD spectrum of a low spin complex. The near infrared MCD spectrum suggests that the alkaline form of native horseradish peroxidase has a 6th ligand somehow different from a normal nitrogen ligand such as histidine or lysine. It implicates that the alkaline form has an overall ligand field strength of between the low spin component of metmyoglobin hydroxide and metmyoglobin azide.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0006-3002
pubmed:author
pubmed:issnType
Print
pubmed:day
23
pubmed:volume
493
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
340-51
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1977
pubmed:articleTitle
Magnetic circular dichroism studies on acid and alkaline forms of horseradish peroxidase.
pubmed:publicationType
Journal Article