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  • 1
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Analytical chemistry 26 (1954), S. 1059-1059 
    ISSN: 1520-6882
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Calcified tissue international 34 (1982), S. 54-58 
    ISSN: 1432-0827
    Keywords: Acid phosphatases ; Acid phosphoprotein phosphatases ; Bone phosphatases ; Ferrous iron ; Ascorbic acid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The effect of ferrous iron (Fe2+) and the reducing agents cysteine, dithiothreitol, and especially ascorbate on acid phosphatase activity was determined in vitro. Activity was extracted from homogenates of suckling rat tibia and femur with hypertonic KCl and Triton X-100, treated with protamine to remove interfering macromolecules, and dialyzed. Tartrate-sensitive and tartrate-resistant activity were separated and partially purified by cation exchange chromatography. At optimum dosage levels, Fe2+ was 100 times more potent than reducing agents in stimulating activity. Hypertonic KCl facilitated the effects of all agents. Fe2+ had no effect on tartrate-sensitive activity (E1), but specifically stimulated the hydrolysis ofβ-glycerophosphate, casein, and especially ATP andp-nitrophenylphosphate (p-NPP) by tartrate-resistant enzyme (E2); other divalent cations were either inhibitory or ineffective over a concentration range of 10−5 to 10−2M. Stimulation of E2 was detectable at 10−6M Fe2+, and the effect was synergistically increased by 10−3M ascorbate. E2 was stimulated maximally at 10−4M Fe2+ + 10−3M ascorbate, but at these concentrations their combined effects were additive. Both stimulated and unstimulated enzyme had identical pH optima (5.8), but the activity of the stimulated enzyme declined more slowly at higher pH values. Hypertonic KCl, Fe2+, or ascorbate reduced one-fourth to one-half the Km of activity withp-NPP substrate, which suggested a direct effect of these substances on E2. It is postulated the Fe2+ may interact with sulfhydryl groups in E2, and that reducing agents and KCl may facilitate this action by (a) maintaining the enzyme in an optimal conformational state, and (b) keeping iron reduced as Fe2+.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Calcified tissue international 33 (1981), S. 261-267 
    ISSN: 1432-0827
    Keywords: Acid phosphatases ; Acid phosphoprotein phosphatases ; Bone phosphatases ; Enzyme purification
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Studies were designed to examine the effects of isotonic sucrose and hypertonic KCl on the extraction and properties of phosphatases (acid optima) from long bones of suckling rats. Low-speed supernatants (S) of homogenates in sucrose were dialyzed against sucrose or deionized H2O. Free enzyme was recovered from both retentates by ultracentrifugation before (S1) or after sequential treatment with KCl and Triton X-100 (S2), protamine (S3), and a final dialysis (S4). Activity was measured withp-nitrophenylphosphate (p-NPP), β-glycerophosphate (β-GP), ATP, and casein. S was evaluated for latent enzyme with hypertonic KCl and classic lysing methods. Fractionation of activity in final extracts was accomplished with CM-52 cellulose or electrophoresis. Results showed that: (a) sucrose did not alter the types or properties of enzymes extracted, but did decrease yield of activities; (b) activity in S was increased approximately 20% by lysing methods, 80% by hypertonic KCl, and was unstable unless salt and detergent were present; and (c) chromatography or electrophoresis of S4 resolved only two enzymes: a tartrate-sensitive phosphomonoesterase (E1) responsible for 15% of the total activity in S, and a tartrate-insensitive enzyme (E2) which accounted for 85% of the activity, was unstable in isotonic medium, had high affinity for ATP andp-NPP, and had low affinity for casein and β-GP. It is concluded that sucrose is not necessary for the isolation of total bone acid phosphatase activity, that hypertonic KCl does not negatively affect the properties of the enzymes isolated, and that E1 and E2 show different latencies.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Calcified tissue international 7 (1971), S. 267-276 
    ISSN: 1432-0827
    Keywords: Tech ; Development ; Enamel ; Enzyme ; Histochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé L'activité en naphtylamidase est étudiéc au niveau des incisives et molaires de rat, à divers stades de développement. Du L-leucyl-4-methoxy-2-naphtylamide, du L-alanyl-4-methoxy-2-naphtylamide, du L-leucyl-2-naphthylamide et du DL-alanyl-2-naphtylamide sont utilisés comme substrats: du bleu rapide B et du grenat rapide GBC sont employés comme sels de diazonium. Le naphtylamidase n'est pas visible au niveau de dents, en voie de dévelopment, au cours de la formation matricielle de l'émail. A la fin de ce stade, le naphtylamidase est présent au niveau de l'extrémité distale des améloblastes, près de la surface de l'émail. L'activité enzymatique reste identique jusqu'au moment de la fusion de l'épithélium dentaire et de l'épithélium buccal, au moment de l'éruption de la dent dans la cavité buccale. On ne rencontre pas de naphtylamidase au niveau d'autres tissues dentaires; cependant une activité marquée est observée dans les ostéoclastes au niveau des surfaces de résorption de l'os alvéolaire, entourant les dents, en voie de développement et d'éruption, et dans certaines régions du tissu conjonctif.
    Abstract: Zusammenfassung Die Aktivität der Naphthylamidase wurde in den Backen- und Schneidezähnen von Ratten in verschiedenen Entwicklungsstufen studiert. Als Substrate wurden L-leucyl-4-methoxy-2-naphthylamid, L-alanyl-4-methoxy-2-naphthylamid, L-leucyl-2-naphthylamid und DL-alanyl-2-naphthylamid verwendet; als Diazoniumsalze dienten Echtblau B und Echt-Granat GBC. Naphthylamidase konnte während der Schmelzmatrixbildung im Zahn nicht nachgewiesen werden. Nach Abschluß dieser Phase erschien Naphthylamidase in den distalen Enden der Ameloblasten, nahe bei der Schmelzoberfläche. Die Enzymtätigkeit blieb am selben Ort lokalisiert, bis das Zahnepithel, im Augenblick wo der Zahn in die Mundhöhle durchstößt, in das Mundepithel überging. Naphthylamidase wurde in anderen Zahngeweben nicht gefunden, aber eine deutliche Aktivität konnte in gewissen Bezirken des Bindegewebes sowie in den Osteoklasten der resorbierenden Oberflächen vom alveolären Knochen festgestellt werden, welcher die sich bildenden und die hervorstoßenden Zähne umgibt.
    Notes: Abstract Naphthylamidase activity was studied in rat molar and incisor teeth at different stages of development. L-leucyl-4-methoxy-2-naphthylamide, L-alanyl-4-methoxy-2-naphthylamide, L-leucyl-2-naphthylamide and DL-alanyl-2-naphthylamide were used as substrates and Fast blue B and Fast Garnet GBC as diazonium salts. Naphthylamidase was not demonstrable in the teeth during enamel matrix formation. After the termination of this stage, naphthylamidase was present in the ameloblasts in their distal ends close to the enamel surface. The enzyme activity retained this localization until the dental epithelium fused with the oral epithelium at the time of tooth eruption into the oral cavity. Naphthylamidase was not found in other dental tissues, but marked activity was found in osteoclasts at the resorbing surfaces of alveolar bone surrounding the developing and erupting teeth and in certain areas of the connective tissue.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 267 (1977), S. 630-632 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] la,25-(OH)2D3 has been called the hormonal form of the vitamin4, because its formation in the kidney4 as well as its circulating level is apparently stringently controlled. Evidence for such regulation is the absence of an increase in the blood level of this metabolite in the face of a many-fold ...
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Calcified tissue international 24 (1977), S. 187-190 
    ISSN: 1432-0827
    Keywords: Column chromatography ; Acidβ-glycerophosphatase ; Acid inorganic pyrophosphatase ; Acid p-nitrophenylphosphatase ; Bone phosphatases
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Extracts of tibiae of suckling rats were prepared with 0.3 M KCl containing 0.1% Triton X-100 and were chromatographed with CM-52 cellulose. Most of the acid phosphatase activity determined with p-nitrophenylphosphate (p-NPP) was bound to the cellulose and could be eluted with a sodium acetate buffer gradient in 2 distinct peaks. The major peak, E2, was bound strongly to the cellulose and showed high activity with p-NPP and inorganic pyrophosphate (P-Pi), but only slight activity withβ-glycerophosphate (β-GP) and was unaffected by tartrate. The minor peak, E1, was weakly bound to the adsorbent, showed equal activity with p-NPP andβ-GP, but negligible activity with P-Pi and was completely inhibited by tartrate. These results support earlier evidence suggesting that bone contains at least 2 different acid phosphatases and that the more abundant enzyme may function as a pyrophosphatase.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Calcified tissue international 27 (1979), S. 219-226 
    ISSN: 1432-0827
    Keywords: Acid phosphatases ; Bone phosphatases ; ATPase ; Enzyme purification
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Acid phosphatase activity in homogenized tibiae and femora of suckling rats was extracted with 0.3M KCl and 0.1% Triton X-100. A high-speed supernatant was treated with protamine sulfate, dialyzed, and chromatographed on CM-52 cellulose. All of the acid phosphatase activity was eluted with a sodium acetate buffer and combined ionic strength-pH gradient into two peaks (E1 and E2). Both enzyme peaks were further purified with Sephadex G-200, which resulted in 700- and 1000-fold purification for E2 and E1, respectively. A total of 220 units (µmoles substrate/min) of E2 with a specific activity of 160 units/mg protein has been obtained in one run by this procedure. E1 has a high molecular weight (〉100,000) and shows preference for monophosphate ester substrates, is markedly inhibited by tartrate, and has a pH optimum near 5. E2 has a lower molecular weight (〈40,000) and shows negligible activity with monophosphate esters [except withp-nitrophenyl phosphate (p-NPP)], but high activity with ADP and ATP. E2 is unaffected by tartrate and shows a pH optimum near 6. Both enzymes are competitively inhibited by inorganic phosphate, and E2, but not E1, is markedly inhibited byp-chloromercuribenzoate. Withp-NPP as substrate, E1 and E2 have distinctly different values for Km. E1 appears similar to the high molecular weight acid phosphatases of soft tissues. However, E2 appears to differ from the low molecular weight phosphatases in soft tissues with regard to substrate specificity.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Journal of molecular histology 8 (1976), S. 543-558 
    ISSN: 1573-6865
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Synopsis Lactate dehydrogenase (LDH) was localized in osteoclasts of fixed and unfixed 19-day chick embryo tibias using a copper ferrocyanide capture reaction and osmiophilic polymer generation. This study revealed that: (1) LDH activity in fixed, briefly rinsed osteoclasts was associated principally with limiting membranes of cytoplasmic vacuoles and vesicles and with the plasma membrane; (2) LDH activity in unfixed osteoclasts was associated only with mitochondria; and (3) some mitochondria were stained in fixed tissue given a long rinse. These results indicate that: cytoplasmic LDH diffused out of unfixed tissue; mitochondrial LDH was inactivated by formaldehyde in fixed tissue; and formaldehyde-inhibited mitochondrial LDH can be reactivated by a long rinse. Although the vesicles that stained for LDH activity were found in all parts of the cell, they were concentrated near the ruffled border, and there is evidence that they contained material from the bone surface. These results suggest that the LDH associated with cytoplasmic vesicles of the osteoclast may be important in processing of material resorbed from the bone surface and that osteoclastic mitochondria may utilize lactate from the bone fluid for energy production.
    Type of Medium: Electronic Resource
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