INTERMICROSOMAL DISTRIBUTION OF AROMATIZING ENZYME SYSTEM IN EQUINE TESTICULAR TISSUE

1973 ◽  
Vol 72 (2) ◽  
pp. 366-375 ◽  
Author(s):  
Ran Oh ◽  
Bun-ichi Tamaoki
Keyword(s):  
Microsomal Fraction ◽  
Density Gradient Centrifugation ◽  
Enzyme System ◽  
Gradient Centrifugation ◽  
Electron Microscopic Examination ◽  
Sucrose Density Gradient ◽  
Testicular Tissue ◽  
Electron Microscopic ◽  
Sucrose Density Gradient Centrifugation ◽  
Cytochrome P 450

ABSTRACT The microsomal fraction (10 000–105 000 × g precipitate) of equine testes was fractionated into the smooth- and the rough-surfaced microsomal subfractions by a sucrose density-gradient centrifugation in the presence of CsCl. The validity of this fractionating procedure was confirmed by electron microscopic examination and also by chemical analysis of the RNA contents in these subfractions. The aromatizing enzyme system (19-hydroxylase and aromatase) which was concentrated in the microsomal fractions among the organellae was found to be localized in the smoothsurfaced microsomal fraction. The cytochrome P-450 which was also involved in the process of enzymatic aromatization was detected exclusively in the smooth-surfaced microsomal fraction. The distribution of the aromatizing system between the two microsomal subfractions of equine testes was discussed in comparison with that in human full term placentae.

scholarly journals Incorporation of [14C]glucosamine and [14C]leucine into mouse kidney β-glucuronidase induced by gonadotrophin

1970 ◽  
Vol 117 (1) ◽  
pp. 161-167 ◽  
Author(s):  
Keitaro Kato ◽  
Hiroyuki Ide ◽  
Tsuranobu Shirahama ◽  
William H. Fishman
Keyword(s):  
Endoplasmic Reticulum ◽  
Microsomal Fraction ◽  
Density Gradient Centrifugation ◽  
Gradient Centrifugation ◽  
Sucrose Density Gradient ◽  
Mouse Kidney ◽  
Differential Centrifugation ◽  
Freezing And Thawing ◽  
Sucrose Density Gradient Centrifugation ◽  
Glucuronidase Activity

Male BALB/C mice were injected intraperitoneally with 2.5 i.u. of gonadotrophin. After the injection, increase of β-glucuronidase activity was first observed in the microsomal fraction. By 36h 45–50% of the total homogenate activity was found in the microsomal fraction compared with 20–25% in the control microsomal fraction. From 36 to 80h not only microsomal β-glucuronidase but also lysosomal β-glucuronidase increased progressively. After 69h stimulation with 2.5 i.u. of gonadotrophin, d-[1-14C]glucosamine or l-[U-14C]leucine was injected intraperitoneally. After a further 3h the kidneys were homogenized and five particulate fractions were prepared by differential centrifugation. The β-glucuronidase in the microsomal and lysosomal fractions was released respectively by ultrasonication and by freezing and thawing treatment. The enzyme was purified by organic-solvent precipitation and by sucrose-density-gradient centrifugation. The results demonstrated the incorporation of these two labels into the mouse renal β-glucuronidase. The microsomal β-glucuronidase was much more radioactive than the lysosomal enzyme and approx. 80% of the newly synthesized enzyme appeared in microsomes and approx. 20% of that was found in lysosomes at this period. These results suggest that the mouse renal β-glucuronidase is a glycoprotein and that the newly synthesized enzyme is transported from endoplasmic reticulum to lysosomes.

New evidence for an intermediate polymer of glucose in cellulose biosynthesis by Acetobacter xylinum

1975 ◽  
Vol 21 (2) ◽  
pp. 111-120 ◽  
Author(s):  
J. Kjosbakken ◽  
J. Ross Colvin
Keyword(s):  
Alkaline Solution ◽  
Density Gradient Centrifugation ◽  
Enzyme System ◽  
Gradient Centrifugation ◽  
Sucrose Density Gradient ◽  
Acetobacter Xylinum ◽  
Cellulose Biosynthesis ◽  
Sucrose Density Gradient Centrifugation ◽  
A Cell ◽  
New Evidence

The results of sucrose-density-gradient centrifugation of a cell-free particulate enzyme system from Acetobacter xylinum which was incubated with uridine diphosphoglucose indicate that there is a polymeric intermediate in the biosynthesis of cellulose. This intermediate has the properties of an oligomer of glucose, is normally attached to the heaviest particle of the suspension, but, when released by hydrolysis, is preferentially adsorbed to fragments of preformed cellulose. It may form short segments of microfibrils when precipitated from alkaline solution by ethanol. The presence of this intermediate raises again the question of a primer in cellulose biosynthesis.

Purification and properties of boticin P produced by Clostridium botulinum

1974 ◽  
Vol 20 (3) ◽  
pp. 385-390 ◽  
Author(s):  
A. H. S. Lau ◽  
R. Z. Hawirko ◽  
C. T. Chow
Keyword(s):  
Density Gradient ◽  
Clostridium Botulinum ◽  
Density Gradient Centrifugation ◽  
Gradient Centrifugation ◽  
Gel Filtration ◽  
Electron Microscopic Examination ◽  
Equilibrium Density ◽  
Type B ◽  
Electron Microscopic ◽  
Sucrose Density Gradient Centrifugation

A bacteriocin produced spontaneously by a nontoxigenic strain of Clostridium botulinum, type E, PM-15, has been isolated and designated boticin P. It was purified by ammonium sulfate precipitation, gel filtration on Sephadex G-100, sucrose density gradient centrifugation, and cesium chloride equilibrium density gradient centrifugation. Boticin P is composed mainly of proteins (98.8%) with a trace amount of carbohydrates (0.4%), and has an apparent molecular weight in excess of 4 × 106 daltons as estimated by gel filtration on Sepharose 2B. Electron microscopic examination of boticin P reveals a phage tail-like structure of 100 nm in length.Boticin P exerted a static effect on vegetative growth and spore outgrowth but not on the initial events of germination. The boticin was active on 10/12 toxigenic and 3/6 nontoxigenic type E and 2/2 nonproteolytic type B strains of C. botulinum. The activity spectrum on 27 strains supports the proposal that type E and the nonproteolytic type B strains belong to the same taxosubspecies.

scholarly journals GOLGI FRACTIONS PREPARED FROM RAT LIVER HOMOGENATES

1973 ◽  
Vol 59 (1) ◽  
pp. 45-72 ◽  
Author(s):  
J. H. Ehrenreich ◽  
J. J. M. Bergeron ◽  
P. Siekevitz ◽  
G. E. Palade
Keyword(s):  
Rat Liver ◽  
Microsomal Fraction ◽  
Density Gradient Centrifugation ◽  
Gradient Centrifugation ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Sucrose Density Gradient ◽  
Sucrose Density Gradient Centrifugation ◽  
Liver Homogenates ◽  
Main Component

In devising a new procedure for the isolation of Golgi fractions from rat liver homogenates, we have taken advantage of the overloading with very low density lipoprotein (VLDL) particles that occurs in the Golgi elements of hepatocytes ∼90 min after ethanol is administered (0.6 g/100 g body weight) by stomach tube to the animals. The VLDLs act as morphological markers as well as density modifiers of these elements. The starting preparation is a total microsomal fraction prepared from liver homogenized (1:5) in 0.25 M sucrose. This fraction is resuspended in 1.15 M sucrose and loaded at the bottom of a discontinuous sucrose density gradient. Centrifugation at ∼13 x 106 g·min yields by flotation three Golgi fractions of density >1.041 and <1.173. The light and intermediate fractions consist essentially of VLDL-loaded Golgi vacuoles and cisternae. Nearly empty, often collapsed, Golgi cisternae are the main component of the heavy fraction. A procedure which subjects the Golgi fractions to hypotonic shock and shearing in a French press at pH 8.5 allows the extraction of the content of the Golgi elements and the subsequent isolation of their membranes by differential centrifugation.

The Combining Ability of Glycoproteins IIb, IIIa and Ca2+ in EDTA-Treated Nonaggregable Platelets

1983 ◽  
Vol 50 (04) ◽  
pp. 848-851 ◽  
Author(s):  
Marjorie B Zucker ◽  
David Varon ◽  
Nicholas C Masiello ◽  
Simon Karpatkin
Keyword(s):  
Density Gradient ◽  
Combining Ability ◽  
Density Gradient Centrifugation ◽  
Gradient Centrifugation ◽  
Electrophoretic Pattern ◽  
Sucrose Density Gradient ◽  
Irreversible Loss ◽  
Sucrose Density Gradient Centrifugation ◽  
Crossed Immunoelectrophoresis ◽  
Triton X

SummaryPlatelets deprived of calcium and incubated at 37° C for 10 min lose their ability to bind fibrinogen or aggregate with ADP when adequate concentrations of calcium are restored. Since the calcium complex of glycoproteins (GP) IIb and IIIa is the presumed receptor for fibrinogen, it seemed appropriate to examine the behavior of these glycoproteins in incubated non-aggregable platelets. No differences were noted in the electrophoretic pattern of nonaggregable EDTA-treated and aggregable control CaEDTA-treated platelets when SDS gels of Triton X- 114 fractions were stained with silver. GP IIb and IIIa were extracted from either nonaggregable EDTA-treated platelets or aggregable control platelets with calcium-Tris-Triton buffer and subjected to sucrose density gradient centrifugation or crossed immunoelectrophoresis. With both types of platelets, these glycoproteins formed a complex in the presence of calcium. If the glycoproteins were extracted with EDTA-Tris-Triton buffer, or if Triton-solubilized platelet membranes were incubated with EGTA at 37° C for 30 min, GP IIb and IIIa were unable to form a complex in the presence of calcium. We conclude that inability of extracted GP IIb and IIIa to combine in the presence of calcium is not responsible for the irreversible loss of aggregability that occurs when whole platelets are incubated with EDTA at 37° C.

scholarly journals Alteration of hepatic glucocorticoid receptor stability and nuclear binding in vitro by citrate

1983 ◽  
Vol 210 (1) ◽  
pp. 259-263 ◽  
Author(s):  
J Hubbard ◽  
M Kalimi
Keyword(s):  
Glucocorticoid Receptor ◽  
Glucocorticoid Receptors ◽  
Density Gradient Centrifugation ◽  
Gradient Centrifugation ◽  
Deae Cellulose ◽  
Sucrose Density Gradient ◽  
Sucrose Density Gradient Centrifugation ◽  
Nuclear Binding ◽  
Wide Range

Citrate greatly stabilized rat hepatic unbound glucocorticoid receptors in cell-free conditions at 4 degrees C with optimal effectiveness at 5-15 mM. Control receptors were inactivated at 4 degrees C with a half-life of less than 12 h. However, in the presence of 10 mM-citrate, unbound receptors were almost completely stabilized for 48 h at 4 degrees C. Citrate at a concentration of 1-2 mM yielded half-maximal stabilization. The stabilizing effect of citrate was rather specific, as succinate, alpha-oxoglutarate, oxaloacetate, malate and pyruvate had no apparent stabilizing action. Citrate stabilized receptors over a wide range of H+ concentrations, with complete protection between pH 6.5 and 8.5. In addition, citrate appeared to have a significant effect on glucocorticoid-receptor complex activation into a nuclear binding form. Thus 5-10 mM-citrate enhanced nuclear binding, with optimal activation achieved at 10 mM concentration. As analysed by sucrose-density-gradient centrifugation and DEAE-cellulose chromatography, no apparent change was observed in the physical characteristics of the glucocorticoid receptor in the presence of citrate.

3 ß-Hydroxysteroid Oxidoreductase in Suspension Cultures of Digitalis lanata EH RH

1990 ◽  
Vol 45 (9-10) ◽  
pp. 963-972 ◽  
Author(s):  
Hildegard Maria Warneck ◽  
Hanns Ulrich Seitz
Keyword(s):  
Incubation Temperature ◽  
Density Gradient Centrifugation ◽  
Gradient Centrifugation ◽  
Sucrose Density Gradient ◽  
Cell Compartment ◽  
Sucrose Density Gradient Centrifugation ◽  
Ph Optimum ◽  
Digitalis Lanata ◽  
Substrate Kinetics ◽  
Soluble Part

Abstract A 3 β-hydroxysteroid oxidoreductase was isolated and characterized in the microsomes of Digitalis lanata cell cultures. The enzyme catalyzes the conversion of 5α-pregnane-3,20-dione to 5a-pregnan-3 β-ol-20-one and requires NAD(P)H2. The enzyme was found to have a pH optimum of 80. The reaction had an optimum incubation temperature of 25 °C with linear reduction for the first 4 h, reaching maximum enzyme activity after 7 h. Substrate kinetics for 5a-pregnane-3,20-dione and NADPH2 resulted in apparent Km-values of 18.5-20 (µM for 5a-pregnane-3,20-dione and 50-120 µM for the co-substrate NADPH2. In order to localize 3β-hydroxysteroid oxidoreductase differential centrifugation as well as linear sucrose density gradient centrifugation were performed. The results obtained lead to the conclusion that 3β-hydroxysteroid oxidoreductase is not associated with a single cell compartment, but consists of a major soluble part and a markedly smaller part of endoplasmic reticulum-associated activity

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