Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.5.1.52 (PNGase F)
 1,527 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Aldehyde fixation of tissues often adversely affects the reactivity of cellular proteins with antibodies. A most commonly used retrieval technique in immunohistochemistry is high-temperature microwave heating of sections from formaldehyde-fixed and paraffin-embedded tissues. Here we report that pretreatment of paraffin and ultrathin cryosections with N-glycanase F to remove N-glycosidically linked oligosaccharides can result in a dramatic increase in specificity and intensity of immunogold labeling for sugar moieties present on O-glycosidically linked oligosaccharides. This is demonstrated in the immunolocalization of poly alpha2,8 KDN (KDN, 2-keto-3-deoxy-D-glycero-D-galacto-nononic acid) of megalin in rat kidney. The mechanism of this retrieval procedure is most probably based on the elimination of sterical hindrance by large N-glycosidically linked oligosaccharides. Furthermore, we demonstrate that exposure of ultrathin cryosections to acidic conditions (pH 5.5) at ambient temperature prior to immunogold labeling can result in an increased labeling intensity. This effect was observed for megalin immunoreactive sites in proximal tubular epithelia of rat kidney. It is proposed that the mechanism of this retrieval procedure is based on the depolymerization of methylen and polymethylen bridges introduced by formaldehyde in the acidic milieu.
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PMID:Unconventional antigen retrieval for carbohydrate and protein antigens. 986 Feb 59

In this study, N-linked glycans from intact, formalin treated and formalin fixed paraffin embedded (FFPE) standard glycoproteins, human serum and mouse tumor tissue samples were investigated in respect to their susceptibility for formaldehyde treatment mediated changes. FFPE samples were first deparaffinized, followed by solubilization in radioimmunoprecipitation assay buffer and treated with PNGase F for N-glycan release. The released glycans were labeled with a charged fluorophore and analyzed by capillary electrophoresis with laser induced fluorescent detection. No significant alterations were found in the N-glycome profile at any of the investigated complexation levels (i.e., glycoprotein, serum and tissue samples) of the study. These results suggest that FFPE samples can be readily used for global N-glycome analysis holding the promise to find novel carbohydrate biomarkers in prospective and retrospective studies. Exoglycosidase based carbohydrate sequencing was also applied to reveal some basic structural information about the N-linked carbohydrates of the mouse tumor tissue samples.
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PMID:N-Glycosylation analysis of formalin fixed paraffin embedded samples by capillary electrophoresis. 2657 20