Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01189 (beta-endorphin)
 21,003 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Using two immunocytochemical methods, we have shown in light microscopy that the met-enkephalin-like immunoreactivity within striatum and spinal cord of the rat is differentially distributed in either perikarya or nerve terminals according to the technical conditions used [1]. The present electron microscopic study has been undertaken in order to elucidate the subcellular localization of immunoprecipitates according to the same technical conditions. In the neostriatum, numerous met-enkephalin-containing perikarya were stained (principally at the level of rough endoplasmic reticulum) when tissue sections were treated with hydrogen peroxide (H2O2) only, prior to the immunocytochemical procedure. However, injections of colchicine were required to demonstrate perikarya in the dorsal horn of the spinal cord. At variance with previous results, numerous dendritic profiles and nerve terminals were also reactive in this condition. Neurotubules, mitochondria, large granular vesicles (LGVs) and small synaptic vesicles were stained within these structures. The addition of a low concentration of Triton-X-100 (0.02%) in the first incubation medium often resulted in the disappearance of most perikarya and in the staining of only LGVs in nerve terminals. The addition of a higher concentration of Triton-X-100 (0.1%) produced diffusion of immunoprecipitates at the level of nerve terminals, which was probably responsible for the increased intensity of staining and, subsequently, for the better demonstration of fibre varicosities in light microscopy. On the contrary, the disappearance of reactive perikarya seemed to result from the diffusion of the non-protected peptide out of the cytoplasm. The diverse ultrastructural localizations of met-enkephalin-like immunoreactivity in striatum and spinal cord are finally discussed in light of intrinsic connections or afferents described in the literature.
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PMID:Met-enkephalin-like immunoreactivity in rat forebrain and spinal cord using hydrogen peroxide and Triton X-100. Ultrastructural study. 636 52

Neutral tryptophan (*Trp) and tyrosine (TyrO(*)) radicals are repaired by certain flavonoids in buffer, in micelles and in human serum albumin (HSA) with corresponding formation of semioxidized flavonoid radicals. In deaerated buffer, *Trp but not TyrO(*) radicals react with catechin. In micelles, quercetin and rutin repair both *Trp and TyrO(*) radicals. In addition to amino acid reactivity, microenvironmental factors and nature of the flavonoids govern this repair. Electron transfer efficiencies from quercetin to negatively charged *Trp radicals are 100% in the micellar pseudophases of positively charged cetyltrimethylammonium bromide, (CTAB), and neutral Triton X100 (TX100), but 55% in negatively charged sodium dodecyl sulfate (SDS). In oxygen-saturated CTAB micelles, quercetin also reacts with the superoxide radical anion. When bound to domain IIA of HSA, quercetin repairs, by intra- or intermolecular encounter, less than 20% of oxidative damage to HSA. Quercetin can also repair freely circulating oxidized molecules with repair efficiencies falling to 7% for oxidized *Trp, Tyr and alpha-MSH and to less than 2% for urate radical. This limited effectiveness is attributed both to the inaccessibility of bound quercetin and rutin toward radicals of circulating molecules and to the diffusion-controlled recombination of these radicals.
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PMID:Mechanisms of flavonoid repair reactions with amino acid radicals in models of biological systems: a pulse radiolysis study in micelles and human serum albumin. 1220 44

Neutral tryptophan (*Trp) and tyrosine (TyrO(*)) radicals are repaired by certain flavonoids in buffer, in micelles and in human serum albumin (HSA) with corresponding formation of semioxidized flavonoid radicals. In deaerated buffer, *Trp but not TyrO(*) radicals react with catechin. In micelles, quercetin and rutin repair both *Trp and TyrO(*) radicals. In addition to amino acid reactivity, microenvironmental factors and nature of the flavonoids govern this repair. Electron transfer efficiencies from quercetin to negatively charged *Trp radicals are 100% in the micellar pseudophases of positively charged cetyltrimethylammonium bromide, (CTAB), and neutral Triton X100 (TX100), but 55% in negatively charged sodium dodecyl sulfate (SDS). In oxygen-saturated CTAB micelles, quercetin also reacts with the superoxide radical anion. When bound to domain IIA of HSA, quercetin repairs, by intra- or intermolecular encounter, less than 20% of oxidative damage to HSA. Quercetin can also repair freely circulating oxidized molecules with repair efficiencies falling to 7% for oxidized Trp, Tyr and alpha-MSH and to less than 2% for urate radical. This limited effectiveness is attributed both to the inaccessibility of bound quercetin and rutin toward radicals of circulating molecules and to the diffusion-controlled recombination of these radicals.
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PMID:Mechanisms of flavonoid repair reactions with amino acid radicals in models of biological systems: a pulse radiolysis study in micelles and human serum albumin. 1204 90