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101.
The lysosomal enzyme binding protein (receptor protein) isolated from monkey brain was immobilised on Sepharose 4B and used
to study the binding of brain lysosomal enzymes. The immobilised protein could bind \-D-glucosaminidase, α-D-mannosidase,
α-L-fucosidase and2-D-glucuronidase. The bound enzymes could be eluted either at an acid pH of 4.5 or by mannose 6-phosphate
but not by a number of other sugars tested. Binding could be abolished by prior treatment of the lysosomal enzymes with sodium
periodate. Alkaline phosphatase treatment of the enzymes did not prevent the binding of the lysosomal enzymes to the column
but decreased their affinity, as seen by a shift in their elution profile, when a gradient elution with mannose 6-phosphate
was employed. These results suggested that an ‘uncovered’ phosphate on the carbohydrate moiety of the enzymes was not essential
for binding but can enhance the binding affinity. 相似文献
102.
Dr. Erich Buchner Sigrid Buchner Garrett Crawford William T. Mason Paul M. Salvaterra David B. Sattelle 《Cell and tissue research》1986,246(1):57-62
Summary Using a monoclonal antibody selective for the acetylcholine (ACh)-synthesizing enzyme choline acetyltransferase (ChAT) of Drosophila melanogaster we find ChAT-like immunoreactivity in specific synaptic regions throughout the brain of Drosophila melanogaster apart from the lobes and the peduncle of the mushroom body and most of the first visual neuropile (lamina). Several anatomically well-defined central brain structures exhibit particularly strong binding. Characteristic differential staining patterns are observed for each of the four neuromeres of the optic lobes. Cell bodies appear not to bind this antibody. The prominent features of the distribution of ChAT-like immunoreactivity are paralleled by the distribution of acetylcholine hydrolyzing enzymatic activity as revealed by histochemical staining for acetylcholine esterase (AChE). These results are discussed in comparison with published data on enzyme distribution, choline uptake and ACh receptor binding in the nervous system of Drosophila melanogaster. 相似文献
103.
Expression of epidermal growth factor receptor and associated glycoprotein on cultured human brain tumor cells 总被引:3,自引:0,他引:3
P A Steck G E Gallick S A Maxwell W S Kloetzer R B Arlinghaus R P Moser J U Gutterman W K Yung 《Journal of cellular biochemistry》1986,32(1):1-10
The expression of epidermal growth factor (EGF-R) in normal glial and glioma cells grown in culture was examined by using several independent assays. Immunoprecipitation with the monoclonal antibody R1 of extracts from metabolically labeled glial and glioma cells revealed a protein of Mr approximately 170,000, with a migration in sodium dodecyl sulfate-polyacrylamide gels identical to the EGR-R of A431 epidermal carcinoma cells. Furthermore, in the majority of glioma extracts, a protein of Mr approximately 190,000 was specifically immunoprecipitated by this antibody. Similar results were obtained by immunoblotting with a second antibody directed against a synthetic peptide in the sequence of the v-erb-B oncogene. In cell lines expressing both proteins, each was specifically phosphorylated on tyrosine in immune complex kinase assays. The majority of glioma cells bound between 40,000 to 80,000 125I-labeled epidermal growth factor molecules per cell. These results suggest that the expression of EGF-R is common in cultured human glioma cells. In addition, a structurally related protein, is expressed in some of these cells. 相似文献
104.
Kurt Kraeuchi Anna Wirz-Justice Tadaomi Morimasa Rosi Suetterlin-Willener Hans Feer 《Chronobiology international》1986,3(2):127-133
Specific binding of [3H]-imipramine in the rat suprachiasmatic nuclei, occipital cortex and caudate putamen underwent significant and replicable changes throughout 24 hr under a light-dark cycle or under constant conditions. Daily variations were also found in the medial and dorsal raphe nuclei and the lateral hypothalamus. Methamphetamine, a psychoactive drug with marked effect on circadian rhythms in physiological and hormonal parameters and adrenergic receptors, did not have any significant effect on imipramine binding rhythms in eight discrete brain regions. Thus a drug known to reduce serotoninergic neurotransmission did not change characteristics of the modulatory binding site related to serotonin uptake. 相似文献
105.
The Na+ channel activity (tetrodotoxin sensitive 22Na+ flux induced by veratridine and/or anemone toxin II) was studied in two fractions of brain cell plasma membranes, named A and B, isolated by the method of Gray and Whittaker ((1962) J. Anat. 96, 79–87) from rats 5, 10, 30 and 60 days old. The 22Na+ flux was measured in membrane vesicles formed by the isolated membranes, in the absence of drugs (control), in the presence of veratridine, and in the presence of veratridine plus tetrodotoxin. Fraction A consists primarily of neuronal and glial membranes in rats of 5 and 10 days of age, while in the older rats this fraction becomes enriched in myelin. In Fraction A of 5-day-old and 10-day-old rats, veratridine (25 μM) increases the 22Na+ flux 2.4- and 1.6-fold, respectively, and the increment continues to diminish with age, until it becomes negligible in the 60-day-old rats. Fraction B consists of synaptosomes and membrane vesicles, and at the four ages studied veratridine (25 μM) causes an increment of the 22Na+ flux of about 2.5-fold. Fractions A and B from 10-day-old rats, and Fraction B from 60-day-old rats, which are sensitive to veratridine, also respond to anemone toxin II. When veratridine is used in presence of anemone toxin II (0.5 μM), the for veratridine is diminished and the maximum 22Na+ flux is increased. The increments of 22Na+ flux caused by veratridine and/or anemone toxin II in Fractions A and B are blocked by tetrodotoxin ( approx. 5 nM). Fraction A from 60-day-old rats could be subfractionated by osmotic shock and sucrose gradient centrifugation to obtain three subfractions, two of which are enriched in axolemma and display Na+ chennel activity. The other subfraction is enriched in myelin and shows no Na+ channel actiivty. The plasma membrane preparations from young rats (up to 10 days) are devoid of myelin and are useful for studies of Na+ channel activity. 相似文献
106.
A sensitive and specific assay method for cysteine sulfinic acid (CSA) and cysteic acid (CA) using high-performance liquid chromatography has been developed. The method includes post-column derivatization of various amino acids with o-phthalaldehyde in the presence of 2-mercaptoethanol. The column packed with cation-exchange resin (, Shimadzu Sci entific instruments, Inc., Kyoto, Japan) was used for obtaining general separation of amino acids except CSA and CA, while the separation of CSA and CA was achieved using a strong-base anion exchange (, Shimadzu Scientific Instruments) column. The fluorescence peak area for CSA was linear between 20 pmol and 5 nmol, whereas that for CA was 10 pmol to 5 nmol. The regional distribution of CSA, CA, and other amino acids in the rat brain was studied using this new assay method. 相似文献
107.
Multiple Forms of Choline-O-Acetyltransferase in Mouse and Rat Brain: Solubilization and Characterization 总被引:13,自引:12,他引:1
Three forms of acetyl coenzyme A: choline-O-acetyltransferase (EC 2.3.1.6, ChAT) have been isolated from mouse and rat forebrain synaptosomes with a 100 mM sodium phosphate (NaP) buffer of pH 7.4, a high-salt solution (500 mM NaCl), and a 2% Triton DN-65 solution, respectively. The Triton-solubilized form of ChAT differed from the other two forms in its capacity to acetylate homocholine, its pH profile, and its sensitivity to denaturation. NaCl-solubilized ChAT could be distinguished from the other two forms with respect to pH profile, sensitivity to inhibition by 4-(1-naphthylvinyl) pyridine (in the presence of Triton), and apparent Km value for choline acetylation. The caudate and putamen of rat brain contained the highest amount of ChAT activity, based on tissue wet weight, and the cerebellum contained the least of the brain regions examined; only the cerebellum had more membrane-bound than soluble ChAT. Septal lesion reduced ChAT activity in the NaP- and Triton-solubilized fractions prepared from hippocampus by 68% and 64%, respectively, whereas it reduced the activity of the NaCl-solubilized fraction by only 21%. These results suggest that three different forms of ChAT may exist in both mouse and rat brain. 相似文献
108.
Abstract: Stores of methionine-enkephalin were labelled on the N -terminal by incubation of whole brain slices with [3 H]tyrosine (10 °Ci/ml). The 3 H radioactivity corresponding to the position of authentic Met-enkephalin after extraction on Amberlite XAD2 and separation by thin-layer chromatography was taken as an index of synthesis. Maximal incorporation of the labelled tyrosine into Met-enkephalin was attained after 4 h of incubation at 37°C and was inhibited in the presence of 10 μ M cycloheximide. Isolated nerve terminals failed to incorporate any [3 H]tyrosine. The labelled compound had opiatelike activity and consisted of the same five amino acids as an authentic standard. Incubations with leucine aminopeptidase indicated that the labelled tyrosine was on the N -terminus and removal of this tyrosine resulted in loss of opiate-like activity. The incorporation of [14 C]glycine, selected as an alternative precursor, was consistent with de novo synthesis and not N -terminal exchange. A radioimmunoassay was also used to quantify the amount of labelled Met-enkephalin. KCl (50 m M ) elicited a Ca2+ -dependent release of the synthesised [3 H]Met-enkephalin from whole brain slices and also from isolated nerve terminals. The release of Met-enkephalin radioimmunoactivity paralleled that of [3 H]met-enkephalin. Preliminary investigations have suggested that carbamyl choline inhibited this release and its effect was partially reversed by atropine. 相似文献
109.
V Natarajan P C Schmid P V Reddy M L Zuzarte-Augustin H H Schmid 《Journal of neurochemistry》1983,41(5):1303-1312
Abstract: Dog brain homogenates and subcellular preparations incubated in the presence of Ca2+ produced a new phospholipid that was isolated and identified by its infrared spectrum and by chemical degradation as a mixture of 1, 2-diacyl, alkenylacyl, and alkylacyl sn -glycero-3-phospho ( N -acyl)ethanolamines, 50, 45, and 5%, respectively. The N -acyl groups consisted almost exclusively of 16:0, 18:0, and 18:1 fatty acids. Formation of N -acylethanolamine phospholipids from endogenous substrates was linear for about 90 min at approximately 4.5 nmol/h/mg protein and exhibited a pH optimum of 10. Biosynthetic activity was associated with particulate fractions, primarily microsomes, synaptosomes, and mitochondria, but not with myelin. In each case, small amounts (∼0.5 nmol/h/mg protein) of long-chain N -acylethanolamines were also produced. Incubation of dog brain microsomes with 1,2-di[1'-14 C]palmitoyl glycero-phosphocholine yielded N -acylethanolamine phospholipids labeled at both N -acyl (55%) and O -acyl (45%) moieties. It appears that dog brain organelles may contain a phosphatidylethanolamine N -acyl transferase (transacylase) analogous to that recently demonstrated in the myocardial tissue. 相似文献
110.
Effect of alpha-fluoromethylhistidine on the histamine content of the brain of W/Wv mice devoid of mast cells: turnover of brain histamine 总被引:5,自引:1,他引:4
K Maeyama T Watanabe A Yamatodani Y Taguchi H Kambe H Wada 《Journal of neurochemistry》1983,41(1):128-134
In the brains of W/Wv mutant mice that have no mast cells, the histidine decarboxylase (HDC) level is as high as in the brain of congenic normal mice (+/+), but the histamine content is 53% of that of +/+ mice. The effects of alpha-fluoromethylhistidine (alpha-FMH) on the HDC activity and histamine content of the brain of W/Wv and +/+ mice were examined. In both strains, 30 min after i.p. injection of alpha-FMH the HDC activity of the brain had decreased to 10% of that in untreated mice. The histamine content decreased more gradually, and after 6 h about half of the control level remained in +/+ mice, whereas histamine had disappeared almost completely in W/Wv mice. It is concluded that the portion of the histamine content that was depleted by HDC inhibitor in a short time is derived from non-mast cells, probably neural cells. The half-life of histamine in the brain of W/Wv mice was estimated from the time-dependent decrease in the histamine content of the brain after administration of alpha-FMH: 48 min in the forebrain, 103 min in the midbrain, and 66 min in the hindbrain. 相似文献