Pyroglutamic acid

Abraham, George N.; Podell, David N.

doi:10.1007/978-94-009-8027-3_11

Cited by 10 publications

(13 citation statements)

References 36 publications

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“…In all mouse strains analyzed, the QC/isoQC enzymatic activity in ventral brain was 5‐times higher than in cortex and 10‐times higher than in hippocampus. The high enzymatic activity in ventral brain is consistent with the reported function of QC in hypothalamic peptide hormone maturation (Abraham and Podell, 1981; Böckers et al, 1995; Busby et al, 1987; Fischer and Spiess, 1987; Folkers et al, 1970), and with the immunohistochemical demonstration of robust QC expression in hypothalamus, EWN and LC of mouse brain (Hartlage‐Rübsamen et al, 2009; Morawski et al, 2010). However, based on the low proportion (0.5–2%) of QC‐immunoreactive neurons in neocortex and on the lower QC mRNA levels in parietal cortex compared to the hippocampus (Hartlage‐Rübsamen et al, 2009), it was surprising to observe a QC/isoQC enzymatic activity in neocortex twice as high as in hippocampus in all mouse strains.…”

Section: Discussionsupporting

confidence: 84%

“…QC catalyzes the formation of a pyroglutamate (pGlu) residue from glutamine at the N‐terminus of several neuropeptides and peptide hormones such as orexin A, gastrin, gonadotropin‐ and thyrotropin‐releasing hormone, and neurotensin (Busby et al, 1987; Fischer and Spiess, 1987; Awade et al, 1994). This pGlu modification is important for the biological activity of these peptides and confers stability against proteolytical degradation (Abraham and Podell, 1981; Folkers et al, 1970).…”

Section: Introductionmentioning

confidence: 99%

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Mouse strain and brain region‐specific expression of the glutaminyl cyclases QC and isoQC

Höfling

Indrischek

Höpcke

et al. 2014

Intl J of Devlp Neuroscience

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Glutaminyl cyclases (QCs) catalyze the formation of pyroglutamate (pGlu) from glutamine precursors at the N-terminus of a number of peptide hormones, neuropeptides and chemokines. This post-translational modification stabilizes these peptides, protects them from proteolytical degradation or is important for their biological activity. However, QC is also involved in a pathogenic pGlu modification of peptides accumulating in protein aggregation disorders such as Alzheimer's disease and familial Danish and familial British dementia. Its isoenzyme (isoQC) was shown to contribute to aspects of inflammation by pGlu-modifying and thereby stabilizing the monocyte chemoattractant protein CCL2. For the generation of respective animal models and for pharmacological treatment studies the characterization of the mouse strain and brain region-specific expression of QC and isoQC is indispensible. In order to address this issue, we used enzymatic activity assays and specific antibodies to detect both QC variants by immunohistochemistry in nine different mouse strains. Comparing different brain regions, the highest enzymatic QC/isoQC activity was detected in ventral brain, followed by cortex and hippocampus. Immunohistochemical stainings revealed that QC/isoQC activity in cortex mostly arises from isoQC expression. For most brain regions, the highest QC/isoQC activity was detected in C3H and FVB mice, whereas low QC/isoQC activity was present in CD1, SJL and C57 mice. Quantification of QC- and isoQC-immunoreactive cells by unbiased stereology revealed a higher abundance of isoQC- than of QC-immunoreactive neurons in Edinger-Westphal nucleus and in substantia nigra. In the locus coeruleus, however, there were comparable densities of QC- and of isoQC-immunoreactive neurons. These observations are of considerable importance with regard to the selection of appropriate mouse strains for the study of QC/isoQC relevance in mouse models of neurodegeneration and neuroinflammation and for the testing of therapeutical interventions in these models.

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Section: Discussionsupporting

confidence: 84%

Section: Introductionmentioning

confidence: 99%

Mouse strain and brain region‐specific expression of the glutaminyl cyclases QC and isoQC

Höfling

Indrischek

Höpcke

et al. 2014

Intl J of Devlp Neuroscience

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“…Pyroglutamic acid is also a product of enzymatic activity (that is, pyrrolidone carboxyl peptidase or L‐pyroglutamyl‐peptide hydrolase) on free glutamine or N‐terminal glutamine or glutamic acid present in proteins (Mucchetti and others 2000). In some cases, pyroglutamic acid is associated with off‐flavors, but is also associated with the characteristic flavor of some aged cheeses (Abraham and Podell 1981; Mucchetti and others 2000). In the current study, thermal degradation is unlikely considering the low processing temperature (< 35 °C) that the dressing experienced.…”

Section: Resultsmentioning

confidence: 99%

Production of Shelf‐Stable Ranch Dressing Using High‐Pressure Processing

Waite¹,

Jones²,

Turek³

et al. 2009

Journal of Food Science

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High-pressure processing (HPP) can reduce or eliminate microorganisms of concern in food without deteriorating product quality; however, quality benefits must justify the substantial capital investment for the utilization of this technology. HPP is particularly a beneficial preservation technology for products damaged by thermal treatments or when product quality could be improved by reformulation to raise pH or eliminate chemical preservatives. The primary objectives of this study were to determine the efficacy of HPP to protect premium ranch dressing (pH 4.4) from microbial spoilage and to assess changes in physical, chemical, and sensory attributes throughout the product's shelf life. In inoculated-packages studies, the efficacy of HPP was measured against ranch dressing spoilage organisms: Pediococcus acidilactici, Lactobacillus brevis, and Torulaspora delbrueckii. HPP treatment (600 MPa, 3 min) decreased population of P. acidilactici, the most pressure-resistant spoilage organism tested, by >or= 6.4 log CFU/g. During a shelf-life study of edible product, treating ranch dressing at 600 MPa for 5 min effectively prevented microbial spoilage throughout the storage period (26 wk at 4 and 26 degrees C). The pH and emulsion stability of ranch dressing were not adversely influenced by HPP. Extended storage of HPP product for 16 to 26 wk at 26 degrees C resulted in a decrease in consumer acceptance and significant changes in color and organic acid profile (specifically, increased pyroglutamic acid). These changes were consistent with those expected during extended storage of commercially available products. HPP may be used to produce premium ranch dressing, with defined shelf-life and storage conditions, without significantly changing product attributes.

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“…Xylitol is known to be metabolized in the pentose-phosphate pathway and is a key intermediate in the biosynthesis of aromatic amino acids (13). L-pyroglutamic acid is a cyclical amino acid and may be utilized during amino acid metabolic pathways or biosynthesis of proteins as the amino-terminal residue (1). The increased utilization of…”

Section: Effect Of Desiccation On Specific Substrate Utilization Of Hmentioning

confidence: 99%

Application of the BIOLOG microplate system to monitor the physiological response of heat-stressed bacteria

McCarroll¹

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The BIOLOG microplate system was originally evaluated by Miller and Rhoden (1991) for its ability to correctly identify clinical and environmental isolates. The system determines identity based on the exchange of electrons produced during utilization of a carbon substrate and subsequent respiration, leading to the reduction of a tetrazolium-based color change. Enteric bacteria (Escherichia coli, Enterobacter sakazakii, and Salmonella enterica serovar Typhimurium) were exposed to heat stress (52°C) and samples were removed as a function of time (0, 15, 30 and 90 min). Stressed cells were monitored with traditional viable cell counts and inoculated into BIOLOG GN plates. The stress response of enteric bacteria results in both physical changes, as reflected by their D-values and sublethal injury, and metabolic changes, as reflected by differential utilization of carbon substrates. Results indicate that the BIOLOG system may be used as a tool to monitor the physiological change of heat-stressed enteric bacteria. The BIOLOG system allows for three types of analysis of the metabolic changes taking place in heat-stressed enteric bacteria. The first two applications of the BIOLOG system demonstrated a generalized approach using AWCD and guild groupings as a tool to monitor physiological changes of heat-stressed enteric bacteria. The use of AWCD and guild groupings proved to be relatively ineffective in monitoring physiological changes in heat-stressed enteric bacteria. The third application that may be used demonstrate possible specific substrate utilization differences in heat-stressed enteric bacteria. Notable changes in specific substrate utilization were observed in thermally-stressed enteric bacteria with the use of the BIOLOG system.

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Pyroglutamic acid

Cited by 10 publications

References 36 publications

Mouse strain and brain region‐specific expression of the glutaminyl cyclases QC and isoQC

Mouse strain and brain region‐specific expression of the glutaminyl cyclases QC and isoQC

Production of Shelf‐Stable Ranch Dressing Using High‐Pressure Processing

Application of the BIOLOG microplate system to monitor the physiological response of heat-stressed bacteria

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