scholarly journals ANALYTICAL STUDY OF MICROSOMES AND ISOLATED SUBCELLULAR MEMBRANES FROM RAT LIVER

1974 ◽  
Vol 61 (1) ◽  
pp. 201-212 ◽  
Author(s):  
Alain Amar-Costesec ◽  
Henri Beaufay ◽  
Maurice Wibo ◽  
Denise Thinès-Sempoux ◽  
Ernest Feytmans ◽  
...  
Keyword(s):  
Analytical Study ◽  
Microsomal Fraction ◽  
Chemical Constituents ◽  
Microsomal Protein ◽  
High Yield ◽  
Marker Enzymes ◽  
Cytoplasmic Granules ◽  
Liver Homogenates ◽  
Nadph Cytochrome C Reductase ◽  
Phosphatase Alkaline

Liver homogenates have been submitted to quantitative fractionation by differential centrifugation. Three particulate fractions: N (nuclear), ML (large granules), and P (microsomes), and a final supernate (S) have been obtained. The biochemical composition of the microsomal fraction has been established from the assay and distribution pattern of 25 enzymatic and chemical constituents. These included marker enzymes for mitochondria (cytochrome oxidase), lysosomes (acid phosphatase and N-acetyl-ß-glucosaminidase), and peroxisomes (catalase). The microsomal preparations were characterized by a moderate contamination with large cytoplasmic granules (only 6.2% of microsomal protein) and by a high yield in microsomal components. Enzymes such as glucose 6-phosphatase, nucleoside diphosphatase, esterase, glucuronyltransferase, NADPH cytochrome c reductase, aminopyrine demethylase, and galactosyltransferase were recovered in the microsomes to the extent of 70% or more. Another typical behavior was shown by 5'-nucleotidase, alkaline phosphatase, alkaline phosphodiesterase I, and cholesterol, which exhibited a "nucleomicrosomal" distribution. Other complex distributions were obtained for several constituents recovered in significant amount in the microsomes and in the ML or in the S fraction.

Biosynthesis of Phosphatidic Acid in Mitochondria and Microsomes Via the Acylation of sn-Glycero-3-phosphate

1972 ◽  
Vol 50 (8) ◽  
pp. 936-948 ◽  
Author(s):  
J. B. Davidson ◽  
N. Z. Stanacev
Keyword(s):  
Phosphatidic Acid ◽  
Subcellular Fraction ◽  
Microsomal Fraction ◽  
Specific Activity ◽  
Marker Enzymes ◽  
Acyltransferase Activity ◽  
Isolated Mitochondria ◽  
Direct Acylation ◽  
Submitochondrial Fractions ◽  
Nadph Cytochrome C Reductase

Nuclei-free homogenate, prepared from guinea pig livers, was fractionated into subcellular particles which were then examined for the activities of two microsomal marker enzymes, glucose-6-phosphatase and NADPH: cytochrome c reductase. In an incubation system containing sn-glycero-3-phosphate, fatty acid, and various cofactors the intracellular distribution of acyl-CoA: sn-glycero-3-phosphate acyltransferase(s) was studied and compared with the distribution of the two microsomal marker enzymes.Results obtained showed that the highest specific activity for the acylation of sn-glycero-3-phosphate was associated with the microsomal fraction and the activity in each subcellular fraction paralleled activities of the two microsomal marker enzymes. Furthermore, the amount of acyl-CoA: sn-glycero-3-phosphate acyltransferase activity observed in the mitochondrial and submitochondrial fractions could be accounted for by the content of endoplasmic reticulum as determined by the marker enzymes. This observation was also true for brain, heart, and kidney, as well as for rat liver.These results are interpreted as evidence that isolated mitochondria are unable to synthesize phosphatidic acid by direct acylation of sn-glycero-3-phosphate.

scholarly journals GOLGI FRACTIONS PREPARED FROM RAT LIVER HOMOGENATES

1973 ◽  
Vol 59 (1) ◽  
pp. 73-88 ◽  
Author(s):  
J. J. M. Bergeron ◽  
J. H. Ehrenreich ◽  
P. Siekevitz ◽  
G. E. Palade
Keyword(s):  
Endoplasmic Reticulum ◽  
Cytochrome C ◽  
Rat Liver ◽  
Microsomal Fraction ◽  
Companion Paper ◽  
Transferase Activity ◽  
Ethanol Treatment ◽  
Liver Homogenates ◽  
Cytochrome P 450 ◽  
Nadph Cytochrome C Reductase

The three Golgi fractions isolated from rat liver homogenates by the procedure given in the companion paper account for 6–7% of the protein of the total microsomal fraction used as starting preparation. The lightest, most homogeneous Golgi fraction (GF1) lacks typical "microsomal" activities, e.g., glucose-6-phosphatase, NADPH-cytochrome c-reductase, and cytochrome P-450. The heaviest, most heterogeneous fraction (GF3) is contaminated by endoplasmic reticulum membranes to the extent of ∼15% of its protein. The three fractions taken together account for nearly all the UDP-galactose: N-acetyl-glucosamine galactosyltransferase of the parent microsomal fraction, and for ∼70% of the activity of the original homogenate. Omission of the ethanol treatment of the animals reduces the recovery by half. The transferase activity is associated with the membranes of the Golgi elements, not with their content. Galactose is transferred not only to N-acetyl-glucosamine but also to an unidentified lipid-soluble component.

scholarly journals ANALYTICAL STUDY OF MICROSOMES AND ISOLATED SUBCELLULAR MEMBRANES FROM RAT LIVER

1974 ◽  
Vol 61 (1) ◽  
pp. 188-200 ◽  
Author(s):  
Henri Beaufay ◽  
Alain Amar-Costesec ◽  
Ernest Feytmans ◽  
Denise Thinès-Sempoux ◽  
Maurice Wibo ◽  
...  
Keyword(s):  
Cytochrome C ◽  
Rat Liver ◽  
Analytical Study ◽  
Microsomal Fraction ◽  
Density Gradient Centrifugation ◽  
Gradient Centrifugation ◽  
Cytochrome C Reductase ◽  
Nadh Cytochrome ◽  
Nadph Cytochrome C Reductase

The series introduced by this paper reports the results of a detailed analysis of the microsomal fraction from rat liver by density gradient centrifugation. The biochemical methods used throughout this work for the determination of monoamine oxidase, NADH cytochrome c reductase, NADPH cytochrome c reductase, cytochrome oxidase, catalase, aminopyrine demethylase, cytochromes b5 and P 450, glucuronyltransferase, galactosyltransferase, esterase, alkaline and acid phosphatases, 5'-nucleotidase, glucose 6-phosphatase, alkaline phosphodiesterase I, N-acetyl-ß-glucosaminidase, ß-glucuronidase, nucleoside diphosphatase, aldolase, fumarase, glutamine synthetase, protein, phospholipid, cholesterol, and RNA are described and justified when necessary.

Further Studies upon Chemical Factors Affecting the Breeding of Anopheles in Trinidad

1934 ◽  
Vol 25 (4) ◽  
pp. 491-494 ◽  
Author(s):  
P. A. Buxton
Keyword(s):  
Analytical Study ◽  
Chemical Constituents ◽  
Physical Factors ◽  
Factors Affecting ◽  
Early Stages ◽  
Freshwater Biology ◽  
Chemical Technique ◽  
Chemical Factors ◽  
Physical And Chemical

During the last decade, entomologists have made progress in understanding the environment in which certain insects live; in particular, we begin to understand the effect of certain physical and chemical factors, which make up a part of the environment. With this gain in knowledge, it is sometimes possible to forecast outbreaks of insects and of diseases conveyed by them, and one can sometimes say that a particular alteration of the environment will result in loss or gain. But so far as mosquitos are concerned, one must admit that though much work has been devoted to the analytical study of the water in which the early stages are passed, the results are disappointing. A consideration of the published work suggests several reasons for this. Investigation into the ecology of the mosquito has had a vogue, and much of it has been done by workers who were isolated and whose knowledge of chemical technique and freshwater biology was limited. Apart from that, the inherent difficulties are great, for the worker must hunt for the limiting chemical and physical factors among a host of others which are doubtless unimportant, and there are few clues to indicate which of the chemical constituents of the water affects the mosquito. The data are therefore voluminous and it is difficult to reduce them to order and present them so that they can be readily understood.

scholarly journals The latency of rat liver microsomal protein disulphide-isomerase

1985 ◽  
Vol 228 (3) ◽  
pp. 635-645 ◽  
Author(s):  
N Lambert ◽  
R B Freedman
Keyword(s):  
Endoplasmic Reticulum ◽  
Rat Liver ◽  
High Speed ◽  
Microsomal Fraction ◽  
Membrane Integrity ◽  
Microsomal Protein ◽  
Permeability Barrier ◽  
Rat Liver Microsomes ◽  
Luminal Surface ◽  
Protein Disulphide Isomerase

Protein disulphide-isomerase (PDI) activity was not detectable in freshly prepared rat liver microsomes (microsomal fraction), but became detectable after treatments that damage membrane integrity, e.g. sonication, detergent treatment or freezing and thawing. Maximum activity was detectable after sonication. Identical latency was observed in microsomes prepared by gel filtration and in those prepared by high-speed centrifugation. PDI activity was latent in all particulate subcellular fractions, but not latent in the high-speed supernatant. When all fractions were sonicated to expose total PDI activity, PDI was found at highest specific activity in the microsomal fraction and co-distributed with marker enzymes of the endoplasmic reticulum. Washing of microsomes under various conditions that removed peripheral proteins and, in some cases, bound ribosomes did not remove significant quantities of PDI, nor did it affect the latency of PDI activity. Treatment of microsomes with proteinases, under conditions where the permeability barrier of the microsomal vesicles was maintained intact, did not inactivate PDI significantly or affect its latency. PDI was very readily solubilized from microsomal vesicles by low concentrations of detergents, which removed only a fraction of the total microsomal protein. In all these respects, PDI resembled nucleoside diphosphatase, a marker peripheral protein of the luminal surface of the endoplasmic reticulum, and differed from NADPH: cytochrome c reductase, a marker integral protein exposed at the cytoplasmic surface of the membrane. The data are compatible with a model in which PDI is loosely associated with the luminal surface of the endoplasmic reticulum, a location consistent with the proposed physiological role of the enzyme as catalyst of formation of native disulphide bonds in nascent and newly synthesized secretory proteins.

Capillary electrophoretic chiral separation of hydroxychloroquine and its metabolites in the microsomal fraction of liver homogenates

2006 ◽  
Vol 27 (5-6) ◽  
pp. 1248-1254 ◽  
Author(s):  
Carmem Dickow Cardoso ◽  
Valquíria A. Polisel Jabor ◽  
Pierina Sueli Bonato
Keyword(s):  
Chiral Separation ◽  
Microsomal Fraction ◽  
Capillary Electrophoretic ◽  
Liver Homogenates

scholarly journals Can Homeopathic Arsenic Remedy Combat Arsenic Poisoning in Humans Exposed to Groundwater Arsenic Contamination?: A Preliminary Report on First Human Trial

2005 ◽  
Vol 2 (4) ◽  
pp. 537-548 ◽  
Author(s):  
Anisur Rahman Khuda-Bukhsh ◽  
Surajit Pathak ◽  
Bibhas Guha ◽  
Susanta Roy Karmakar ◽  
Jayanta Kumar Das ◽  
...  
Keyword(s):  
Preliminary Report ◽  
West Bengal ◽  
Reduced Glutathione ◽  
Free Water ◽  
Marker Enzymes ◽  
Human Trial ◽  
Groundwater Arsenic ◽  
Aspartate Amino Transferase ◽  
Globally Distributed ◽  
Phosphatase Alkaline

Groundwater arsenic (As) has affected millions of people globally distributed over 20 countries. In parts of West Bengal (India) and Bangladesh alone, over 100 million people are at risk, but supply of As-free water is grossly inadequate. Attempts to remove As by using orthodox medicines have mostly been unsuccessful. A potentized homeopathic remedy, Arsenicum Album-30, was administered to a group of As affected people and thereafter the As contents in their urine and blood were periodically determined. The activities of various toxicity marker enzymes and compounds in the blood, namely aspartate amino transferase, alanine amino transferase, acid phosphatase, alkaline phosphatase, lipid peroxidation and reduced glutathione, were also periodically monitored up to 3 months. The results are highly encouraging and suggest that the drug can alleviate As poisoning in humans.

scholarly journals Distribution of secretory component in hepatocytes and its mode of transfer into bile

1980 ◽  
Vol 190 (3) ◽  
pp. 819-826 ◽  
Author(s):  
Barbara M. Mullock ◽  
Richard H. Hinton ◽  
Miloslav Dobrota ◽  
Jane Peppard ◽  
Eva Orlans
Keyword(s):  
Particle Size ◽  
Plasma Membrane ◽  
Electron Microscope ◽  
Immunoglobulin A ◽  
Secretory Component ◽  
The Other ◽  
Marker Enzymes ◽  
Liver Homogenates ◽  
Fraction Bound

Immunoglobin A in bile and other external secretions is mostly bound to a glycoprotein known as secretory component. This glycoprotein is not synthesized by the same cells as immunoglobulin A and is not found in blood. We now report the mechanism by which secretory component reaches the bile and describe its function in immunoglobulin A transport across the hepatocyte. Fractionation of rat liver homogenates by zonal centrifugation was followed by measurement of the amounts of secretory component in the various fractions by rocket immunoelectrophoresis. Secretory component was found in two fractions. One of these was identified as containing Golgi vesicles from its isopycnic density and appearance in the electron microscope; the other contained principally fragments of the plasma membrane of the sinusoidal face of the hepatocyte, as shown by its particle size and content of marker enzymes. Only the latter fraction bound 125I-labelled immunoglobulin A added in vitro. At 5min after intravenous injection of [14C]fucose, the secretory component in the Golgi fraction was labelled, but not that in the plasma membrane. The secretory component in the sinusoidal plasma membrane did, however, become labelled before the first labelled secretory component appeared in bile, about 30min after injection. We suggest that fucose is added to the newly synthesized secretory component in the Golgi apparatus. The secretory component then passes, with the other newly secreted glycoproteins, to the sinusoidal plasma membrane. There it remains bound but exposed to the blood and able to bind any polymeric immunoglobulin A present in serum. The secretory component then moves across the hepatocyte to the bile-canalicular face in association with the endocytic-shuttle vesicles which carry immunoglobulin A. Hence there is a lag before newly synthesized secretory component appears in bile.

Evidence for the Biosynthetic Difference between Isolated Mitochondria and Microsomes from Guinea-Pig and Rat Liver Regarding Lysophospharidic Acid, Phosphatidic Acid, CDP-Diglyceride, Phosphatidylglycerol, and Cardiolipin

1974 ◽  
Vol 52 (10) ◽  
pp. 936-939 ◽  
Author(s):  
J. B. Davidson ◽  
N. Z. Stanacev
Keyword(s):  
Guinea Pig ◽  
Phosphatidic Acid ◽  
Rat Liver ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Marker Enzymes ◽  
Synthetic Enzymes ◽  
Isolated Mitochondria ◽  
Significant Difference ◽  
Nadph Cytochrome C Reductase

The enzymatic activities of marker enzymes (NADPH – cytochrome c reductase and glucose-6-phosphatase) and synthetic enzymes (acyl-CoA:sn-glycero-3-phosphate acyltransferase, CTP:sn-3-phosphatidic acid cytidyltransferase, and CDP-diglyceride:sn-glycero-3-phosphate phosphatidyltransferase) were measured in both isolated mitochondria and microsomes from liver of guinea pig and rat. Results thus obtained show a significant difference in activities of these enzymes between subcellular particles within species and between two examined species. The activity of acyl-CoA:glycero-3-phosphate acyltransferase in guinea-pig mitochondria parallels the activity of microsomal marker enzymes in this fraction, while in rat liver mitochondria the activity is relatively higher and cannot be accounted for by the microsomal content as determined by marker enzymes. Implications of these results regarding mitochondrial autonomy in the biosynthesis of polyglycero-phosphatides and their precursors are discussed.

scholarly journals Parotid microsomal Ca2+ transport. Subcellular localization and characterization

1982 ◽  
Vol 208 (3) ◽  
pp. 789-794 ◽  
Author(s):  
P Kanagasuntheram ◽  
T S Teo
Keyword(s):  
Endoplasmic Reticulum ◽  
Parotid Gland ◽  
Subcellular Localization ◽  
Microsomal Fraction ◽  
Narrow Range ◽  
Differential Centrifugation ◽  
Linear Rate ◽  
Rat Parotid Gland ◽  
Rat Parotid ◽  
Nadph Cytochrome C Reductase

Rat parotid gland homogenates were fractionated into mitochondrial, heavy microsomal and light microsomal fractions by differential centrifugation. ATP-dependent 45Ca2+ uptake by the subcellular fractions paralleled the distribution of NADPH-cytochrome c reductase, an enzyme associated with the endoplasmic reticulum. The highest rate of Ca2+ uptake was found in the heavy microsomal fraction. Ca2+ uptake by this fraction was dependent on the presence of ATP and was sustained at a linear rate by 5 mM-oxalate. Inhibitors of mitochondrial Ca2+ transport had no effect on the rate of Ca2+ uptake. Na+ and K+ stimulated Ca2+ uptake. At optimal concentrations. Na+ stimulated Ca2+ uptake by 120% and K+ stimulated Ca2+ uptake by 260%. Decreasing the pH from 7.4 to 6.8 had little effect on Ca2+ uptake. The Km for Ca2+ uptake was 3.7 microM free Ca2+ and 0.19 mM-ATP. Vanadate inhibited Ca2+ uptake; 60 microM-vanadate inhibited the rate of Ca2+ accumulation by 50%. It is concluded that the ATP-dependent Ca2+ transport system is located on the endoplasmic reticulum and may play a role in maintaining intracellular levels of free Ca2+ within a narrow range of concentration.

Sign in / Sign up

Export Citation Format

Share Document