Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 1998 Oct 15;18(20):8126-32.
doi: 10.1523/JNEUROSCI.18-20-08126.1998.

Electrochemical analysis of protein nitrotyrosine and dityrosine in the Alzheimer brain indicates region-specific accumulation

K Hensley  1 , M L Maidt, Z Yu, H Sang, W R Markesbery, R A Floyd
Affiliations

Electrochemical analysis of protein nitrotyrosine and dityrosine in the Alzheimer brain indicates region-specific accumulation

K Hensley et al. J Neurosci. .

Abstract

HPLC with electrochemical array detection (HPLC-ECD) was used to quantify 3,3'-dityrosine (diTyr) and 3-nitrotyrosine (3-NO2-Tyr) in four regions of the human brain that are differentially affected in Alzheimer's disease (AD). DiTyr and 3-NO2-Tyr levels were elevated consistently in the hippocampus and neocortical regions of the AD brain and in ventricular cerebrospinal fluid (VF), reaching quantities five- to eightfold greater than mean concentrations in brain and VF of cognitively normal subjects. Uric acid, a proposed peroxynitrite scavenger, was decreased globally in the AD brain and VF. The results suggest that AD pathogenesis may involve the activation of oxidant-producing inflammatory enzyme systems, including nitric oxide synthase.

PubMed Disclaimer

Figures

Fig. 1.
Fig. 1.
HPLC-ECD chromatogram of a protein digest from an AD brain (SMTG region) illustrating the resolution of peaks assigned to tyrosine (Tyr), 3,3′ dityrosine (diTyr), and 3-nitrotyrosine (3-NO2-Tyr;A). B, C, Expansion of chromatogram in A to illustrate the resolution of dityrosine and nitrotyrosine peaks.
Fig. 2.
Fig. 2.
HPLC-ECD chromatogram of a protein digest from AD brain (SMTG region) chromatographed by using the same column as the sample shown in Figure 1, with the inclusion of LDS in the mobile phase. A, Original sample (full scale = 25 μA current) showing ECD response at 200 mV cell potential (channel 1). The peak marked in A (asterisk) coeluted near 3-NH2-Tyr but differed markedly with respect to oxidation potential (see Results). B, Original sample at 700 mV cell potential (channel 9) illustrating the peak assigned to 3-NO2-Tyr. C, D, Regions of the chromatogram shown in A and B, respectively, after treatment of the sample with hydrosulfite to partially reduce the 3-NO2-Tyr to 3-NH2-Tyr (labeled).
Fig. 3.
Fig. 3.
Quantitation of tyrosine oxidation products in various regions of the AD and normal human brains. Error bars indicate SEM; *p < 0.05.
Fig. 4.
Fig. 4.
Correlation between dityrosine and nitrotyrosine within protein digests from normal and AD brains.
Fig. 5.
Fig. 5.
Dityrosine and nitrotyrosine concentrations in VF from normal and AD subjects. Error bars indicate SEM; *p < 0.05.
Fig. 6.
Fig. 6.
Uric acid content of VF and brain tissue from normal and AD subjects. Error bars indicate SEM. Uric acid concentration was depressed significantly in AD brain (p < 0.05 by ANOVA).
See this image and copyright information in PMC

References

    1. Ahlskog JE, Uitti RJ, Low PA, Tyce GM, Nickander KK, Peterson RC, Kokmen E. No evidence for systemic oxidant stress in Parkinson’s or Alzheimer’s disease. Mov Disord. 1995;10:566–573. - PubMed
    1. Balazs L, Leon M. Evidence of an oxidative challenge in the Alzheimer’s brain. Neurochem Res. 1994;19:1131–1137. - PubMed
    1. Bauer J, Strauss S, Schreiter-Gasser U, Ganter U, Schlegel P, Witt I, Volk B, Berger M. Interleukin 6 and α-2-macroglobulin indicate an acute-phase state in Alzheimer’s disease cortices. FEBS Lett. 1991;285:111–114. - PubMed
    1. Beckman JS, Chen J, Ischiropoulos H, Crow JP. Oxidative chemistry of peroxynitrite. Methods Enzymol. 1994;233:229–240. - PubMed
    1. Braak H, Braak E. Pathology of Alzheimer’s disease. In: Calne DB, editor. Neurodegenerative diseases. Saunders; Philadelphia: 1994. pp. 585–613.

Publication types