Browsing by keyword "Peroxidases"
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How accurate is the determination of blood in gastric juice? Comparison of peroxidase and porphyrin methodsBACKGROUND: Mucosal bleeding is frequently used as a measure of gastric mucosal integrity. We compared the orthotolidine method for quantifying haemoglobin in gastric juice with a method based on measurement of fluorescent porphyrins extracted from haem. We also investigated whether acid or pepsin had a deleterious effect on the results of either method. METHODS: We compared the effects of pH (2 or 7), time (up to 180 min), haemoglobin concentration and the addition of pepsin (2.5, 5 or 7.5 kU/mL hog pepsin) on the accuracy of the two methods. RESULTS: With the orthotolidine method there was a time-dependent decline in detectable haemoglobin concentration (P < 0.02) at pH 2 that was not seen at pH 7. The time- and pH-dependent decline in detectable haemoglobin was not seen using the porphyrin assay. CONCLUSION: The widely used orthotolidine method for determination of blood in gastric juice is less reliable than the porphyrin method as it is more likely to be influenced by acidic conditions in the stomach.
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Saitohin, which is nested in the tau locus and confers allele-specific susceptibility to several neurodegenerative diseases, interacts with peroxiredoxin 6Saitohin is a gene unique to humans and their closest relatives, the function of which is not yet known. Saitohin contains a single polymorphism (Q7R), and its Q and R alleles belong to the H1 and H2 tau haplotype, respectively. The Saitohin Q allele confers susceptibility to several neurodegenerative diseases. To get a handle on Saitohin function, we used it as a bait in a yeast two-hybrid screen. By this assay and subsequent co-immunoprecipitation and glutathione S-transferase pull-down assays, we discovered and confirmed that Saitohin interacts with peroxiredoxin 6, a unique member of that family that is bifunctional and the levels of which increase in Pick disease. The strength of the interaction appeared to be allele-specific, giving the first distinction between the two forms of Saitohin.