Interaction between the soluble and particulate neuraminidases of chick liver.

The sum of the neuraminidase activities found in the isolated soluble and particulate fractions of chick liver was considerably higher than that observed in the cytoplasmic extract from which these fractions were obtained. Addition of increasing amounts of particulate neuraminidase to a constant amount of the soluble preparation resulted in a progressive loss of enzyme activity.     

Localization of acid phosphatases in the cell fractions of chick liver

Summary 3 molecular forms (P1, P2 and P3) of acid phosphatase (E.C.3.1.3.2) have been detected in chicken liver homogenate. The different intracellular localization of these molecules has been demonstrated by cellular fractionation and electrophoretic analysis. P1 and P2 phosphatases are both present in the particulate fraction. P3 is present in a pure form in the soluble fraction. The difference between the enzyme molecules present in the particulate fraction and that in the soluble one is confirmed by the different activation-inhibition effect of various ions and substances on the enzymatic activity of subcellular fractions.     

Characteristic changes of cerebellar proteins associated with cerebellar hypoplasia in jaundiced Gunn rats and the prevention of these by phototherapy

Summary In the cerebellar particulate fractions from Gunn rat homozygotes 3 protein bands with apparent mol.wts of 250,000, 50,000 and 33,000 in SDS-polyacrylamide gel disc electrophoresis underwent major changes, and phototherapy of the newborns could effectively prevent the changes.A part of this research was supported by grants from the Ministry of Education in Japan (No.448131) and the Japan Association for Maternal Welfare.     

Homogenisator für kontinuierliches Homogenisieren zur präparativen Gewinnung von Zellorganellen

Summary Large-scale preparations of tissue homogenates are not conveniently obtained with the conventional Potter-Elvehjem homogenizer. Therefore this homogenizer was modified to permit a continuous pump-driven passage of material through the homogenizer without undue damage to particulate fractions of cells.     

Adenosine 5'-triphosphate sulphurylase from Spirulina platensis.

ATP-sulphurylase from an unicellular blue-green alga, Spirulina platensis was localized in the soluble fractions of cell-free homogenate, and it was stable for over 3 weeks at -6 degrees C.     

Blutagglutinierende und toxische Eiweissfraktionen aus Bohnen

Summary Soluble proteins from black beans (Phaseolus vulgaris) have been separated into 4 fractions, one soluble in 1% NaCl-solution and 3 water soluble. The latter were separated by ammonium sulfate fractionation. The haemagglution of these fractions is compared with their toxicity in mice when applied by intraperitoneal injection. The LD₅₀ of the most active fraction was about 50 mg/kg. When used in mice of different strains, the toxicity was not the same while the blood cells were agglutinated by the same final concentration. Crotonoil-induced papilloma-bearing mice were slightly more resistant than normal animals.     

The compositional analysis of recent cephalopod shell carbohydrates by Fourier transform infrared spectrometry and high performance anion exchange-pulsed amperometric detection

The organic matrix of four living cephalopod skeletons was extracted, purified, separated in a soluble and an insoluble fraction. These fractions were submitted to infrared analysis. After a light hydrolysis, their monosaccharide content was determined by HPAE-PAD. The results were treated by principal component analysis.Infrared analysis has been used to estimate the protein/sugar ratios and showed a high amount of chitin within the insoluble fractions. This was corroborated by their high content of glucosamine. The composition of soluble matrices appeared more heterogeneous: the general tendency is an increase of glucosamine from the most mineralized shell (Nautilus) to the non-mineralized one (Loligo), and a decrease in glucose and galactose. These data would be in agreement with the evolutionary tendency towards shell reduction and disappearance among cephalopods.     

Enzymatic synthesis of trisialoganglioside by particulate fractions of rat liver

Summary Rat liver contains a particulate (membrane-bound) glycosyl transferase, concentrated in Golgi apparatus fractions, which catalyzes the synthesis of a trisialoganglioside from the ganglioside precursor disialohematoside (G_D3). Sialic acid was not incorporated into exogenous G_D1a from CMP-N-acetylneuraminic acid suggesting that G_D1a is an endproduct of the monosialoganglioside pathway. Thus, the disialoganglioside pathway may be a primary source of trisialoganglioside and higher ganglioside homologs in adult rat liver.     

Adenosine 5′-triphosphate sulphurylase fromSpirulina platensis

Summary ATP-sulphurylase from an unicellular blue-green alga,Spirulina platensis was localized in the soluble fractions of cell-free homogenate, and it was stable for over 3 weeks at –6°C.     

Production of superoxide by neutrophils

Cellular and Molecular Life Sciences - Oxygen uptake by neutrophils has been stimulated by particulate serum-treated-zymosan (STZ) and soluble N-formylmethionyl-leucyl-phenylalanine (FMLP) in the...     

Chromate reduction in Streptomyces

Streptomyces species 3M grew in peptone yeast extract medium with 1000 micrograms/ml K2Cr2O7. Incubation of the chromate with different cell fractions in the presence of NADH and NADPH resulted in a decrease of Cr6+ in the reaction mixture. The level of Cr6+ was reduced by 82.7% by a particulate cell fraction obtained by centrifugation at 105,000 x g for 1 h, in the presence of NADH. The reducing enzyme was associated with this cell fraction. The enzyme was constitutive and reduced Cr6+ to Cr3+.     

Cathepsin A/protective protein: an unusual lysosomal multifunctional protein

Cathepsin A/protective protein [3.4.16.5], carboxypeptidase A, is a lysosomal serine protease with structural homology to yeast (Saccharomyces cerevisiae) carboxypeptidase Y. Cathepsin A is a member of the alpha/beta hydrolase fold family and has been suggested to share a common ancestral relationship with other alpha/beta hydrolase fold enzymes, such as cholinesterases. Several lines of evidence indicate that cathepsin A is a multicatalytic enzyme with deamidase and esterase in addition to carboxypeptidase activities. Cathepsin A was recently identified in human platelets as deamidase. In vitro, it hydrolyzes a variety of bioactive peptide hormones including tachykinins, suggesting that extralysosomal cathepsin A plays a role in regulation of bioactive peptide functions. Recent reports emphasize the lysosomal protective function of cathepsin A rather than its protease function. The protective function of cathepsin A is distinct from its catalytic function. Human lysosomal beta-galactosidase and neuraminidase exist as a high molecular weight enzyme complex, in which there is a 54-kDa glycoprotein termed 'lysosomal protective protein'. Based on cell culture studies, protective protein was found to protect both beta-galactosidase and neuraminidase from intralysosomal proteolysis by forming a multienzyme complex and was shown to be deficient in patients with galactosialidosis, a combined deficiency of beta-galactosidase and neuraminidase. Molecular cloning and gene expression studies have disclosed that protective protein is cathepsin A. The cathepsin A precursor has the potential to restore both beta-galactosidase and neuraminidase activities in fibroblasts from patients with galactosialidosis. Cathepsin A knockout mice showed a phenotype similar to human galactosialidosis and the deficient phenotype found in the mutant mice was corrected by transplanting erythroid precursor cells overexpressing cathepsin A. Collectively, these findings demonstrate the significance of cathepsin A as a key molecule in the onset of galactosialidosis and also highlight the therapeutic potential of the cathepsin A precursor for patients with galactosialidosis.     

Developmental and ageing changes in aminopeptidase activities in selected tissues of the rat

Aminopeptidase activities, assayed as arylamidase activities, were investigated in selected tissues of 1, 6, 12 and 24-month-old rats. The enzyme activities were found to have a heterogeneous distribution and age-related changes were observed. The highest levels of soluble arginyl-aminopeptidase activity were detected in brain homogenate at all the studied ages, whereas membrane-bound activity presented the highest levels in brain and kidney in the four ages tested. Aspartyl-aminopeptidase activity was detected mainly in the particulate fraction of kidney at all four ages. In 1, 6 and 12-month-old animals, soluble aspartyl-aminopeptidase activity was also higher in the kidney than in the rest of the tissues, whereas in the group of 2-year-old rats, the highest levels were found in both kidney and liver. Age-related changes were observed in all the studied tissues and for all the assayed enzymatic activities. In general, the maximal levels were detected in both the youngest and the oldest animals, and the minimal ones in 6 and 12-month-old rats. However, in the adrenals, the soluble and membrane-bound arginyl-aminopeptidase activity was higher in 6-month and 2-year-old rats than in 1-month and 12-month-old rats. These changes may reflect the functional status of the susceptible endogenous substrates of aminopeptidases.     

Die Solubilisation der Gehirnneuraminidase durch proteolytische Enzyme

Summary The release of membrane-bound brain neuraminidase from brain homogenate by proteolytic digestion with trypsin, -chymotrypsin and pronase is described. Trypsin shows the highest solubilizing effect. On the basis of the ammoniumsulphate precipitation the pronase-released neuraminidase has the lowest molecular size.     

Activity of rabbit heart on thromboxane synthetase]

The soluble and microsomal fractions of Rabbit myocardium are not able to induce the synthesis of thromboxanes. On the contrary, they inhibit the thromboxane synthetase of various sources. The chemical structure of the active constituent responsible for this activity is not yet known: it is probably neither of an enzymatic nature, nor a protein of high molecular weight.     

Les glycoprotéines sériques dans le granulome expérimental provoqué par la carrageenine

Summary We studied serum glycoproteins in rats and guinea pigs during the development of granulomas, provoked by carrageenin injection. In rats total serum sialic acid was raised as well as sialic acid soluble in sulfosalicylic acid and haptoglobin. The rise of these 2 fractions, seromucoid and haptoglobine accounts quantitatively for the rise of the total sialic acid. In guinea pigs total serum sialic acid was unchanged, but sulfosalicylosoluble sialic acid as well as haptoglobin were much higher than basal values. Quantitatively the serum glycoprotein reaction was much higher in rats than in guinea pigs.     

Hydrogen peroxide generation in Trypanosoma cruzi.

Homogenates from T. cruzi epimastigotes produced 3.4 pmoles H2O2/min 10(6) cells, as detected by the cytochrome c peroxidase assay. Addition of NADH or NADPH increased H2O2 production by a factor of 3 and 5, respectively. When supplemented with NADH and NADPH, the mitochondrial, microsomal and supernatant fractions produced H2O2, the soluble fraction and the mitochondrial membranes being apparently the main generators of H2O2. The epimastigote homogenates showed cyanide-sensitive superoxide dismutase activity, equivalent to 0.28 microgram bovine superoxide dismutase per mg homogenate protein.     

The role of sialic acid in 5-HT binding to synaptic membranes.

The high affinity binding of [14C]5-HT to nerve ending membranes isolated from rat brain is not affected by neuraminidase treatment. The specificity of ligand receptor interaction was demonstrated by displacement studies with tryptamine derivatives, noradrenaline, and acetylcholine.     

Über die farbgebende Gruppe von Crenilabrus-Blau

Summary The blue chromoproteid isolated from the fins ofCrenilabrus pavo C.V. is split by alkali hydrolysis into a protein and a pigment soluble in chloroform. The pigment is identified as biliverdin by its positive Gmelinreaction, the UV and visible absorption spectrum, and the chromatographic behaviour of its dimethyl ester. The lowest molecular weight of the chromoproteid has been evaluated from its biliverdin content to be 37,000±2400; different chromatographic fractions are presumably oligomeres of this unit.

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Herrn Professor Dr.Richard Kuhn zum 65. Geburtstag gewidmet.     

Chromate reduction inStreptomyces

Summary Streptomyces species 3M grew in peptone yeast extract medium with 1000 g/ml K₂Cr₂O₇. Incubation of the chromate with different cell fractions in the presence of NADH and NADPH resulted in a decrease of Cr⁶⁺ in the reaction mixture. The level of Cr⁶⁺ was reduced by 82.7% by a particulate cell fraction obtained by centrifugation at 105,000×g for 1 h, in the presence of NADH. The reducing enzyme was associated with this cell fraction. The enzyme was constitutive and reduced Cr⁶⁺ to Cr³⁺.