scholarly journals Structure, composition, physical properties, and turnover of proliferated peroxisomes. A study of the trophic effects of Su-13437 on rat liver.

1975 ◽  
Vol 67 (2) ◽  
pp. 281-309 ◽  
Author(s):  
F Leighton ◽  
L Coloma ◽  
C Koenig
Keyword(s):  
Enzyme Activities ◽  
Average Diameter ◽  
Urate Oxidase ◽  
Leucine Incorporation ◽  
Acid Oxidase ◽  
Peroxisome Proliferation ◽  
Amino Acid Oxidase ◽  
Liver Size ◽  
Peroxisomal Enzyme ◽  
Trophic Effect

Peroxisome proliferation has been induced with 2-methyl-2-(p-[1,2,3,4-tetrahydro-1-naphthyl]-phenoxy)-propionic acid (Su-13437). DNA, protein, cytochrome oxidase, glucose-6-phosphatase, and acid phosphatase concentrations remain almost constant. Peroxisomal enzyme activities change to approximately 165%, 50%, 30%, and 0% of the controls for catalase, urate oxidase, L-alpha-hydroxy acid oxidase, and D-amino acid oxidase, respectively. For catalase the change results from a decrease in particle-bound activity and a fivefold increase in soluble activity. The average diameter of peroxisome sections is 0.58 +/- 0.15 mum in controls and 0.73 +/- 0.25 mum after treatment. Therefore, the measured peroxisomal enzymes are highly diluted in proliferated particles. After tissue fractionation, approximately one-half of the normal peroxisomes and all proliferated peroxisomes show matric extraction with ghost formation, but no change in size. In homogenates submitted to mechanical stress, proliferated peroxisomes do not reveal increased fragility; unexpectedly, Su-13437 stabilizes lysosomes. Our results suggest that matrix extraction and increased soluble enzyme activities result from transmembrane passage of peroxisomal proteins. The changes in concentration of peroxisomal oxidases and soluble catalase after Su-13437 allow the calculation of their half-lives. These are the same as those found for total catalase, in normal and treated rats, after allyl isopropyl acetamide: about 1.3 days, a result compatible with peroxisome degradation by autophagy. A sequential increase in liver RNA concentration, [14C]leucine incorporation into DOC-soluble proteins and into immunoprecipitable catalase, and an increase in liver size and peroxisomal volume per gram liver, characterize the trophic effect of the drug used. In males, Su-13437 is more active than CPIB, another peroxisome proliferation-inducing drug; in females, only Su-13437 is active.

Age-related physiological studies comparing Candida albicans chlamydospores to yeasts

1979 ◽  
Vol 25 (6) ◽  
pp. 765-772 ◽  
Author(s):  
Sara E. Miller ◽  
W. R. Finnerty
Keyword(s):  
Candida Albicans ◽  
Amino Acid ◽  
Metabolic Activity ◽  
Trypan Blue ◽  
Leucine Incorporation ◽  
Acid Oxidase ◽  
Oxygen Utilization ◽  
Amino Acid Oxidase ◽  
Age Related ◽  
Electron Microscopical

From electron-microscopical observations, a decreased metabolic activity in 3-day-old Candida albicans chlamydospores was suggested, and progressive deterioration in chlamydospores aged 2–8 months was shown. Oxygen utilization by chlamydospore–pseudomycelium (CSP) preparations was less than that by yeast, while 3-day-old CSP preparations used significantly less O2 than 24-h CSP preparations. Amino acid incorporation was greater in yeast than in CSP preparations. Leucine incorporation by 20-h yeasts was twice that of 5-day yeasts and 5 times that of 20-h and 5-day CSP. Amino acid decarboxylation was similar in yeasts and CSP and was determined by end-product analyses to be via amino acid oxidase. Light microscopy autoradiography of [14C]leucine incorporation demonstrated that the metabolic activity in CSP preparations was due to the young growing tips of the pseudomycelium and not to mature chlamydospores. Yeasts did not take up trypan blue but could be stained if first autoclaved or treated with 10% acid or 10% base. Young chlamydospores grown in the presence of trypan blue developed unstained and became permeable to the dye at [Formula: see text] days. These data suggest that chlamydospores of C. albicans do not function in the classical role attributed to spores; i.e., mature chlamydospores cannot germinate, but rather age, deteriorate, and die.

scholarly journals D-aspartate oxidation by rat and bovine renal peroxisomes: an electron microscopic cytochemical study.

1990 ◽  
Vol 38 (9) ◽  
pp. 1377-1381 ◽  
Author(s):  
M E Beard
Keyword(s):  
Amino Acid ◽  
Oxidase Activity ◽  
Electron Microscopic Level ◽  
Acid Oxidase ◽  
Electron Microscopic ◽  
Amino Acid Oxidase ◽  
Cytochemical Localization ◽  
Peroxisomal Enzyme ◽  
Cytochemical Study ◽  
Biochemical Studies

D-amino acid oxidase, a peroxisomal enzyme, and D-aspartate oxidase, a potential peroxisomal enzyme, share biochemical attributes. Both produce hydrogen peroxide in flavin-requiring oxidative reactions. Such similarities suggest that D-aspartate oxidase may also be localized to peroxisomes. Definitive identification of D-aspartate oxidase as a peroxisomal enzyme depends, however, on visualization at the electron microscopic level. Using incubation conditions shown to be specific for the enzyme in biochemical studies, this report extends the cytochemical localization of D-amino acid oxidase to bovine renal peroxisomes, and shows that D-aspartate can be oxidized by rat and bovine renal peroxisomes. An unexpected finding was the sensitivity of both D-amino acid oxidase activity (proline specific) and D-aspartate oxidase activity to inhibition by agents used in biochemical studies to discriminate between the two enzyme activities. Therefore, it is possible that, in the cytochemical system used in this study, (a) either D-proline and D-aspartate are substrates for only one enzyme or (b) the two enzymes have additional overlapping biochemical properties.

scholarly journals COMBINED BIOCHEMICAL AND MORPHOLOGICAL STUDY OF PARTICULATE FRACTIONS FROM RAT LIVER

1965 ◽  
Vol 26 (1) ◽  
pp. 219-243 ◽  
Author(s):  
Pierre Baudhuin ◽  
Henri Beaufay ◽  
Christian de Duve
Keyword(s):  
Electron Microscope ◽  
Amino Acid ◽  
Outer Membrane ◽  
Rat Liver ◽  
Morphological Study ◽  
Urate Oxidase ◽  
Acid Oxidase ◽  
Amino Acid Oxidase ◽  
Experimental Conditions ◽  
Dense Bodies

Six particulate preparations isolated from rat liver under different experimental conditions were analyzed biochemically and examined in the electron microscope. The results confirm the lysosomal nature of the pericanalicular dense bodies and demonstrate that the microbodies are the bearers of urate oxidase, catalase, and D-amino acid oxidase. Catalase, representing a major component of the particles, and D-amino acid oxidase appear to be associated with the structureless "sap" of the particles, urate oxidase with their crystalloid core or with their outer membrane.

scholarly journals The N –methyl D–aspartate receptor glycine site and D–serine metabolism: an evolutionary perspective

2004 ◽  
Vol 359 (1446) ◽  
pp. 943-964 ◽  
Author(s):  
Michael J. Schell
Keyword(s):  
Nmda Receptor ◽  
Divergence Time ◽  
Postnatal Period ◽  
Serine Racemase ◽  
Acid Oxidase ◽  
Glycine Site ◽  
Amino Acid Oxidase ◽  
Sequence Alignments ◽  
Peroxisomal Enzyme ◽  
Serine Metabolism

The N –methyl D–aspartate (NMDA) type of glutamate receptor requires two distinct agonists to operate. Glycine is assumed to be the endogenous ligand for the NMDA receptor glycine site, but this notion has been challenged by the discovery of high levels of endogenous D–serine in the mammalian forebrain. I have outlined an evolutionary framework for the appearance of a glycine site in animals and the metabolic events leading to high levels of D–serine in brain. Sequence alignments of the glycine–binding regions, along with the scant experimental data available, suggest that the properties of invertebrate NMDA receptor glycine sites are probably different from those in vertebrates. The synthesis of D–serine in brain is due to a pyridoxal–5'–phosphate (B 6 )–requiring serine racemase in glia. Although it remains unknown when serine racemase first evolved, data concerning the evolution of B 6 enzymes, along with the known occurrences of serine racemases in animals, point to D–serine synthesis arising around the divergence time of arthropods. D–Serine catabolism occurs via the ancient peroxisomal enzyme D–amino acid oxidase (DAO), whose ontogenetic expression in the hindbrain of mammals is delayed until the postnatal period and absent from the forebrain. The phylogeny of D–serine metabolism has relevance to our understanding of brain ontogeny, schizophrenia and neurotransmitter dynamics.

Oxidases and Oxygenases

2007 ◽  
Author(s):  
Perry A. Frey ◽  
Adrian D. Hegeman
Keyword(s):  
Amino Acid ◽  
Oxygen Atom ◽  
Phenylalanine Hydroxylase ◽  
Urate Oxidase ◽  
Galactose Oxidase ◽  
Ascorbate Oxidase ◽  
Acid Oxidase ◽  
Similar Reaction ◽  
Amino Acid Oxidase ◽  
Hydrolysis Of

An oxidase catalyzes the oxidation of a substrate by O2 without incorporating an oxygen atom into the product. A monooxygenase catalyzes oxidation by O2 with incorporation of one oxygen atom into the product, and oxidation by a dioxygenase proceeds with incorporation of both atoms of O2 into the product. These reactions generally require an organic or metallic coenzyme, with few exceptions, notably urate oxidase. Mechanisms of action of phenylalanine hydroxylase, galactose oxidase, and ascorbate oxidase are provided in chapter 4 in connection with the introduction of metallic coenzymes. In this chapter, we present cases of well-studied coenzyme and metal-dependent oxidases and oxygenases, and we consider one example of an oxidase that does not require a cofactor. Biochemical diversity may be a characteristic of oxidases, which include flavoproteins, heme proteins, copper proteins, and quinoproteins. The actions of copper and topaquinone-dependent amine oxidases are presented in chapter 3, and in chapter 4, two copper-dependent oxidases are discussed. In this chapter, we discuss flavin-dependent oxidases, a mononuclear iron oxidase, and a cofactor-independent oxidase. Flavin-dependent oxidases catalyze the reaction of O2 with an alcohol or amine to produce the corresponding carbonyl compound and H2O2. Examples include glucose oxidase, which produces gluconolactone and H2O2 from glucose and O2 according to. A D-Amino acid oxidase (EC 1.4.3.3) catalyzes a formally similar reaction to produce an α-keto acid from the corresponding α-D-amino acid. The oxidation of an amino acid by an oxidase produces ammonium ion in addition to hydrogen peroxide and the ketoacid, and so it is formally more complex. It proceeds in the three phases described in, the reduction of FAD to FADH2 by the amino acid, hydrolysis of the resultant α-iminoacid to the corresponding α-ketoacid and NH4, and oxidation of FADH2 by O2 to form H2O2. D-Amino acid oxidase is a thoroughly studied example of a flavoprotein oxidase. The enzyme is a 84-kDa homodimer containing one molecule of FAD per subunit. The mechanisms of the hydrolysis of imines and of the oxidation of dihydroflavins are discussed in chapters 1 and 3.

scholarly journals THE SYNTHESIS AND TURNOVER OF RAT LIVER PEROXISOMES

1969 ◽  
Vol 41 (2) ◽  
pp. 521-535 ◽  
Author(s):  
Federico Leighton ◽  
Brian Poole ◽  
Paul B. Lazarow ◽  
Christian De Duve
Keyword(s):  
Amino Acid ◽  
Rat Liver ◽  
Isocitrate Dehydrogenase ◽  
Hydroxy Acid ◽  
Deae Cellulose ◽  
Urate Oxidase ◽  
Acid Oxidase ◽  
Total Proteins ◽  
Amino Acid Oxidase ◽  
Liver Peroxisomes

Rat liver peroxisomes isolated by density gradient centrifugation were disrupted at pH 9, and subdivided into a soluble fraction containing 90% of their total proteins and virtually all of their catalase, D-amino acid oxidase, L-α-hydroxy acid oxidase and isocitrate dehydrogenase activities, and a core fraction containing urate oxidase and 10% of the total proteins. The soluble proteins were chromatographed on Sephadex G-200, diethylaminoethyl (DEAE)-cellulose, hydroxylapatite, and sulfoethyl (SE)-Sephadex. None of these methods provided complete separation of the protein components, but these could be distributed into peaks in which the specific activities of different enzymes were substantially increased. Catalase, D-amino acid oxidase, and L-α-hydroxy acid oxidase contribute a maximum of 16, 2, and 4%, respectively, of the protein of the peroxisome. The contribution of isocitrate dehydrogenase could be as much as 25%, but is probably much less. After dissolution of the cores at pH 11 , no separation between their urate oxidase activity and their protein was achieved by Sephadex G-200 chromatography.

scholarly journals Light and electron microscopic localization of D-aspartate oxidase in peroxisomes of bovine kidney and liver: an immunocytochemical study.

1996 ◽  
Vol 44 (9) ◽  
pp. 1013-1019 ◽  
Author(s):  
K Zaar
Keyword(s):  
Protein A ◽  
Cell Types ◽  
Subcellular Fractionation ◽  
Systematic Investigation ◽  
Kidney Cortex ◽  
Acid Oxidase ◽  
Electron Microscopic ◽  
Amino Acid Oxidase ◽  
Peroxisomal Enzyme ◽  
Bovine Kidney

D-Aspartate oxidase (EC 1.4.3.1; D-ASPOX) specifically oxidizes the D-isomers of dicarboxylic amino acids such as aspartic or glutamic acid. Subcellular fractionation experiments in the past showed its association with peroxisome preparations in kidney cortex and liver. However, no information exists on the in situ localization and distribution of the enzyme in different cell types. We have purified the enzyme from the bovine kidney and raised an antibody against it in rabbits. The monospecificity of the antibody has been confirmed by Western blotting and it does not crossreact with D-amino, acid oxidase. Immunohistochemical localization of the antigen in bovine kidney and liver with the streptavidin-biotin-peroxidase technique revealed a punctate localization in the epithelial cells of proximal nephron tubules, particularly in the straight P-3 segment, as well as in hepatocytes. This is consistent with a localization in peroxisomes. Best results have been obtained with Carnoy-fixed material after paraffin embedding or after fixation with formaldehyde-glutaraldehyde in cryostat sections. Immunoelectron microscopy with protein A-gold confirms the peroxisomal localization of D-ASPOX. Gold particles are distributed over the matrix, suggestive of a peroxisomal matrix enzyme. This is the first report on the localization of D-ASPOX, a little-known peroxisomal enzyme. The techniques described and the antibody prepared will now allow systematic investigation of its tissue distribution.

Inhibition of key enzymes linked to snake venom induced local tissue damage by kolaviron

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Azubuike Ikechukwu Okafor ◽  
Elewechi Onyike
Keyword(s):  
Amino Acid ◽  
Snake Venom ◽  
Tissue Damage ◽  
Enzyme Activities ◽  
Hydrolytic Enzymes ◽  
Phospholipase A ◽  
Acid Oxidase ◽  
Dependent Manner ◽  
Amino Acid Oxidase ◽  
Local Tissue

AbstractObjectivesSnakebite envenoming is an important public health problem that threatens the lives of healthy individuals especially in many tropical countries like Nigeria. Antivenins, the only efficient approach for snakebite envenoming, are limited in their efficacy in the neutralization of local tissue damage. Snake venom phospholipase A2 (PLA2), protease, hyaluronidase and l-amino acid oxidase (LAAO) are the major hydrolytic enzymes involve in local tissue damage. Therefore, this study evaluates the inhibitory effect of kolaviron (KV) against Naja n. nigricollis (NNN) snake venom hydrolytic enzymes involved in local tissue damage.MethodsKolaviron was evaluated for its ability to inhibit the hydrolytic enzyme activities of NNN venom phospholipase A2 (PLA2), protease, hyaluronidase and l-amino acid oxidase (LAAO). Present study also deals with the neutralization of NNN venom enzyme(s) induced complications such as myotoxic, edemic, hemolytic and procoagulant effects.ResultsKolaviron inhibited the PLA2, protease, hyaluronidase and LAAO enzyme activities of NNN venom in a dose-dependent manner. Furthermore, myotoxic, edemic, hemolytic and procoagulant effects induced by NNN venom enzyme were neutralized significantly (p<0.05) when different doses of KV were pre-incubated with venom before assays.ConclusionsThese findings clearly present kolaviron as a potent inhibitor against NNN venom hydrolytic enzymes involved in local tissue damage and may act by either forming an inhibitor-enzyme complex that restricts the substrate availability to the enzyme or direct binding to the enzyme active site that affects the enzyme activity thereby mitigating venom-induced toxicity.

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