Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.3.1 (alkaline phosphatase)
 47,916 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

X-ray absorption near edge structure (XANES) spectra for protein layers adsorbed at liquid interfaces in a Langmuir trough have been recorded for the first time. We studied the parkin protein (so-called E3 ubiquitin ligase), which plays an important role in pathogenesis of Parkinson disease. Parkin contains eight Zn binding sites, consisting of cysteine and histidine residues in a tetracoordinated geometry. Zn K-edge XANES spectra were collected in the following two series: under mild radiation condition of measurements (short exposition time) and with high X-ray radiation load. XANES fingerprint analysis was applied to obtain information on ligand environments around zinc ions. Two types of zinc coordination geometry were identified depending on X-ray radiation load. We found that, under mild conditions, local zinc environment in our parkin preparations was very similar to that identified in hemoglobin, treated with a solution of ZnCl2 salt. Under high X-ray radiation load, considerable changes in the zinc site structure were observed; local zinc environment appeared to be almost identical to that defined in Zn-containing enzyme alkaline phosphatase. The formation of a similar metal site in unrelated protein molecules, observed in our experiments, highlights the significance of metal binding templates as essential structural modules in protein macromolecules.
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PMID:XANES Measurements for Studies of Adsorbed Protein Layers at Liquid Interfaces. 3308 Aug 16

Mitochondrial dysfunction is an early, imminent event in neurodegenerative disorders including Parkinson disease (PD) and Alzheimer disease (AD). The enzymatic pair PINK1 and PRKN/Parkin recognize and transiently label damaged mitochondria with ubiquitin (Ub) phosphorylated at Ser65 (p-S65-Ub) as a signal for degradation via the autophagy-lysosome system (mitophagy). Despite its discovery in cell culture several years ago, robust and quantitative detection of altered mitophagy in vivo has remained challenging. Here we developed a sandwich ELISA targeting p-S65-Ub with the goal to assess mitophagy levels in mouse brain and in human clinical and pathological samples. We characterized five total Ub and four p-S65-Ub antibodies by several techniques and found significant differences in their ability to recognize phosphorylated Ub. The most sensitive antibody pair detected recombinant p-S65-Ub chains in the femtomolar to low picomolar range depending on the poly-Ub chain linkage. Importantly, this ELISA was able to assess very low baseline mitophagy levels in unstressed human cells and in brains from wild-type and prkn knockout mice as well as elevated p-S65-Ub levels in autopsied frontal cortex from AD patients vs. control cases. Moreover, the assay allowed detection of p-S65-Ub in blood plasma and was able to discriminate between PINK1 mutation carriers and controls. In summary, we developed a robust and sensitive tool to measure mitophagy levels in cells, tissue, and body fluids. Our data strongly support the idea that the stress-activated PINK1-PRKN mitophagy pathway is constitutively active in mice and humans under unstimulated, physiological and elevated in diseased, pathological conditions. Abbreviations: Ab: antibody; AD: Alzheimer disease; AP: alkaline phosphatase; CV: coefficient of variation; ECL: electrochemiluminescence; KO: knockout; LoB: Limit of Blank; LoD: Limit of Detection; LoQ: Limit of Quantification; MSD: meso scale discovery; PD: Parkinson disease; p-S65-PRKN: phosphorylated PRKN at serine 65; p-S65-Ub: phosphorylated ubiquitin at serine 65; Std.Dev.: standard deviation; Ub: ubiquitin; WT: wild type.
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PMID:Sensitive ELISA-based detection method for the mitophagy marker p-S65-Ub in human cells, autopsy brain, and blood samples. 3311 98