Hereditary Hemochromatosis (HH) is an inherited recessive autosomal disorder characterized by accumulation of excess iron. When iron binding proteins become saturated, concentrations of free, or non-transferrin-bound iron (NTBI) rise, a condition thought to be responsible for the adverse effects associated with HH. To investigate that disturbing iron homeostasis plays a role in free radical injury in HH, protein carbonyls were
found to be 1-7 times higher in patients with HH than in controls, with the greatest increases being observed in untreated HH patients with high ferritin and >90% transferrin saturation with iron. An Unpaired t test revealed a P value of 0.0278 (P< 0.05), which is considered to be
statistically significant. Our data showed a significant positive correlation (linear relationship) between the level of carbonyl content and ferritin concentration in plasma samples from patients with HH. In vitro oxidation
of transferrin and ferritin standards with hydrogen peroxide and excess iron, followed by
immobilized trypsin digestion (Poroszyme),
high-resolution LC-MS/MS analysis (Q-TOF Ultima, Waters) and MS/MS data processing (PEAKS, Bioinformatics Solution), identified several tryptic peptides containing oxidized Met,Trp and His residues. Mapping of the oxidized ferritin residues showed them to be located on the inner face of each sub-unit, the face directed toward the ferritin core where iron is normally stored. Using the same methodology, oxidized residues were subsequently detected in ferritin and transferrin isolated from plasma samples of patients severely affected with HH. Comparing of MS/MS spectra of in vitro oxidized samples that have most fragment
ion peaks in common with oxidized peptide MS/MS
spectra from samples of patients with HH revealed a significant correlation between the two. These data show that elevated NTBI may be involved in oxidative modification of the iron binding proteins, ferritin and transferrin, and that such modifications may play a significant role in the
pathophysiology of HH.
| Identifer | oai:union.ndltd.org:USASK/oai:usask.ca:etd-11262007-104315 |
| Date | 12 December 2007 |
| Creators | Ahmed, Mohamed S. |
| Contributors | Lehotay, Denis C. |
| Publisher | University of Saskatchewan |
| Source Sets | University of Saskatchewan Library |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://library.usask.ca/theses/available/etd-11262007-104315/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to University of Saskatchewan or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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