Heme octapeptide

Kraehenbuhl, J.P., Calardy, R.E., and Jamieson, J.D. (1974) Preparation and characterization of an immu-noelectron microscope tracer consisting of a heme-octapeptide coupled to Fab. J. Exp. Med. 139, 208. 

Boehringer catalogue 1982-1983 for enzymes. Sigma catalogue 1983 for MPOases (MPOase 8, 9, or 11 are heme octapeptide, nonapeptide or undecapeptide, respectively)-... 

Conjugation of the heme-octapeptide (8-MPOase) to Fab using the /V-hydroxysuccin-imide ester of p-formylbenzoic acid... 

As the protein sequence is covalently attached to the heme in cytochrome c, digestion by pepsin gives rise to a heme undecapeptide, and following by tryptic digestion decreases the length of the attached peptide from eleven residues to eight residues, i.e., to a heme octapeptide [12]. These two peptides aggregate in aqueous... 

Figure 37. Absorption (A and B) and circular dichroism (C and D) spectra of the heme octapeptide at two different concentrations, 1.7 x lO" M (A and C) and 1.7 x 10" M (B and D) with simultaneous resolution of curves A and C and of curves B and D. On going to higher concentration, the positive 358 nm band is seen to increase markedly the 397 nm band changes sign and the negative 408 nm band becomes more intense. Reproduced, with permission, from [13].

Fe(II)(DTPA)] (diethylenetriamine-N,N, N",iV" -pentaacetate) and H2O2 clearly established that the oxidizing species produced is not the hydroxyl radical but an iron-oxo species such as the ferryl ion. This species is formed by a bimolecular reaction, first order in both [H2O2] and [Fe(II)(DTPA) ] with a rate constant of k = 1.37 0.07 x 10 M s The peroxidatic activity of the heme octapeptide from cytochrome c, microperoxidase-8, was measured at 25 C and pH The active form of the substrate was shown to be the hydroperoxide... 

D.W Urry and J.W Pettegrew, Model Systems for Interacting Heme Moieties. II. The Ferri-heme Octapeptide of Cytochrome. J. Am. Chem. Soc., 89,5276-5283,1967. 

Microperoxidase 8 is a heme octapeptide, obtained by enzymatic hydrolysis of heart Cytochrome c, in which a histidine is axially co-ordinated to the heme iron, and acts as a fifth ligand. It exhibits two kinds of activities a peroxidase-like activity and a cytochrome P45o-like activity. Ricoux et al. (2000) have shown that microperoxidase 8 is not only able to oxidise various aliphatic and aromatic hydroxyl-amines with the formation of microperoxidase 8-Fe(II)-nitrosoalkane or -arene complexes absorbing around 414 nm, but also that these complexes can be obtained by reduction of nitroalkanes. 

The active site of cytochrome c, a heme-octapeptide, has been isolated and electron transfer reactions with [ Ru(bipy)3] examined. The... 

Figure 8.5.3. Microperoxidase-8 is a heme octapeptide Glu (glutamic acid), Val (valine), Thr (threonine), His (histidine), Cys (cysteine), Gin (glutamine), Ala (alanine).

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