Molecular forms of acetylcholinesterase in the chicken ciliary ganglion; changes after denervation, axotomy and double section]

Four main molecular forms of acetylcholinesterase (AChE), with sedimentation coefficients of 5, 7.5, 11.5 and 20 S, are found in Chicken ciliary ganglion. After denervation, the loss in 11.5 and 20 S forms occuring in 48 hrs coincides with the disappearance of presynaptic structures. In contrast, axotomy induces an early and durable increase in 7.5 S form. From these results, it is inferred that 11.5 and 20 S forms are predominant in presynaptic structures and 7.5 S form is mainly postsynaptic. In addition, the effects observed after simultaneous denervation and axotomy show a reciprocal control between pre- and postsynaptic elements. Finally, a trans-synaptic effect is exerted on 20 S AChE in controlateral ganglion after preganglionic sections.     

Interconvertibility of molecular forms of 3'5' cyclic AMP phosphodiesterase of human platelets]

Three forms of cyclic AMP phosphodiesterase from human platelets are resolved upon sucrose gradient centrifugation : 2.5S (monomer), 4.8S (dimer) and 7S (tetramer). They are interconvertible and form an association-dissociation equilibrium depending on the concentration of enzyme. The dissociated form has a high Km for cyclic AMP (Km : 3-5.10(-4) M) whereas the associated form has a low Km (Km : 3-5.10(-5) M).     

Multiple forms of human kidney mutarotase

Summary 4 forms of mutarotase from human kidney were demonstrated by DEAE-cellulose column chromatography. A major form of them was purified to homogeneity.     

Developmental forms of human skeletal muscle AMP-deaminase

Chromatography on phosphocellulose revealed the existence of two well-separable forms of skeletal muscle AMP-deaminase in the tissue extracts of 11- and 16-week-old human fetuses. One of these forms elutes from the column at the same salt concentration as the muscle isozyme found in the skeletal muscle extract from adult man, and seems to have similar kinetic properties. The second form, which was found only in vestigial amounts in adult human tissue extract, represents different kinetic properties and seems to be a form characteristic for the fetal period of ontogenesis.     

Molecular forms of dopamine beta-hydroxylase in rat superior cervical ganglion and adrenal gland

Dopamine beta-hydroxylase (DBH) enzyme activity was associated in rat superior cervical ganglion with tetrameric DBH-A (294,000 D) and dimeric DBH-B (147,000 D) and in rat adrenal gland with DBH-A and a novel molecular form of DBH, defined as DBH-C, with a molecular weight of 125,000 D. Pretreatment of the rats with cycloheximide markedly reduced DBH activity without altering the molecular heterogeneity.     

Molecular forms of dopamine beta-hydroxylase in rat superior cervical ganglion and adrenal gland

Summary Dopamine beta-hydroxylase (DBH) enzyme activity was associated in rat superior cervical ganglion with tetrameric DBH-A (294,000 D) and dimeric DBH-B (147,000 D) and in rat adrenal gland with DBH-A and a novel molecular form of DBH, defined as DBH-C, with a molecular weight of 125,000 D. Pretreatment of the rats with cycloheximide markedly reduced DBH activity without altering the molecular heterogeneity.     

In vivo and in vitro differences between leukocytic uptake of oligodeoxynucleotides

Development and application of therapeutic oligonucleotides rely on proper analysis of binding and uptake. We have used several model oligodeoxynucleotides (ODNs) to analyze binding/uptake by rat and human leukocytes. Here we describe: (1) differences between in vivo and in vitro uptake of ODNs to rat leukocytes, (2) differences after injection of lipopolysaccharide (LPS), (3) large in vitro differences between primary mononuclear cells in PBS, plasma and blood, and (4) differences of ODN uptake between rat and human leukocytes. Our data show that ODN uptake by primary blood cells was different in PBS, plasma and blood. In addition, LPS treatment increased ODN uptake by leukocytes in blood, indicating that pathological conditions may influence ODN uptake. Furthermore, ODN uptake in rat and human blood is also different, suggesting that preclinical ODN uptake data from rat blood cannot easily be extrapolated to the human condition. Received 17 December 2007; received after revision 16 January 2008; accepted 5 February 2008     

Molecular aspects of 2 human urinary glycoproteins with histocompatibility antigen (HLA) serological activity]

Two serologically active urinary glycoproteins (HLA-A 9 and HLA-B 12) were isolated from urine provided by a patient suffering from tubular proteinuria. Their N-terminal sequences were automatically determined. The latter were identical with the sequence of another urinary glycoprotein (protein HC). The relationship between protein HC and the serological activity is discussed.     

Molecular mechanism for the production of multiple forms of MM creatine kinase

Incubation of human, canine or rabbit MM creatine kinase with carboxypeptidase-N or B resulted in the production of 2 additional enzyme forms with increased anodal migration on polyacrylamide gels. The C-terminal amino acid of tissue MM creatine kinase from all 3 species was shown to be lysine, a specific substrate for carboxypeptidase-N and B.     

Molecular weight of human alpha2-H-ferroglobulin subunits. Comparison with molecular weight of ferritin subunits]

alpha2 H globulin, a glycoferroprotein, was first demonstrated in the sera of patients with malignant diseases. This protein was isolated from cancerous human liver, and compared with ferritin, a ferroprotein showing some identical properties (presence of iron, high molecular weight, common antigenic determinants). However, physicochemical differences were observed between these two proteins. The study of protein dissociation was performed by polyacrylamide gel electrophoresis in sodium dodecyl sulfate after reduction by mercaptoethanol. A similar molecular weight of 19 000 is obtained for subunits of these two proteins. This value agrees well with the results obtained by other authors for ferritin.     

Molecular deficiencies of human blood coagulation

Summary Blood coagulation reflects, the complex biological system resulting in the formation of thrombin and the subsequent conversion of fibrinogen into fibrin. Disorders of either thrombin or fibrin formation may cause bleeding states. Congential hemorrhagic disorders are characterized by either reduction of a coagulation factor or impairment of its functional capacity by structural aberrations. Immunological studies and direct molecular evaluation of fibrinogen demonstrate that both types of abnormalities occur. Functional evaluation of abnormal fibrinogens suggests that many different structural variants exist and variably influence interaction with thrombin, fibrin polymerization and fibrin stabilization. Similar studies performed on factors II, VII, VIII, IX, X and XIII indicate that qualitative abnormalities are more frequent than true deficiency states. Such molecular abnormalities will become increasingly interesting and important as the biochemistry of normal coagulation progresses.

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Zusammenfassung Blut gerinnt, wenn das Gerinnungsferment Thrombin aktiviert wird und Fibrinogen in Fibrin umwandelt. Störungen der Thrombin- oder Fibrinbildung können Bluterkrankheiten verursachen. Die Ursache angeborener Bluterkrankheiten liegt entweder in der quantitativen Verminderung oder in qualitativen Strukturanomalien eines Gerinnungsfaktors. Immunologische Methoden im Verein mit einer beginnenden, direkten Strukturabklärung zeigten für das Fibrinogen überzeugend, dass beide Möglichkeiten vorkommen. Unterschiedliche Funktionsausfälle von Fibrinogen lassen vermuten, dass verschiedenartigen Strukturanomalien für Störungen der Substrateigenschaften gegenüber Thrombin, der Polymerisierung oder der Fibrinstabilisierung verantwortlich sind. Ähnliche Untersuchungen an den Faktoren II, VII, VIII, IX, X und XIII zeigen, dass wahrscheinlich die Mehrzahl der bekannten Bluterkrankheiten durch Strukturanomalien verursacht werden. Die eingehende Untersuchung solcher Strukturdefekte wird zukünftig um so interessanter und bedeutungsvoller werden, je besser die Struktur und Funktion der normalen Gerinnungsfaktoren bekannt sind.

     

Phospholipid antigens acquired by the young forms of Schistosoma mansoni]

Immunofluorescence studies provide evidence of cardiolipin fixation at the schistosomulum's surface, following incubation with liposomes (cardiolipin-lecithin or cardiolipin-lecithin added with cholesterol). Fixation occurs at 37 degrees C as well as at 0 degree C whether proteins were present or not. Several washes do not remove cardiolipin fixation.     

Identification and characterisation of two allelic forms of human alcohol dehydrogenase 2

The human alcohol dehydrogenase system is comprised of multiple forms that catalyse the oxidation/reduction of a large variety of alcohols and aldehydes. A transition that results in an Ile308Val substitution was identified in the human ADH2 gene by single-strand conformation polymorphism analysis. Screening a Swedish population revealed that Val308 was the most frequent allele (73%), and site-directed mutagenesis was used to obtain both allelozymes, which were expressed in Escherichia coli for characterisation. Thermostability was assayed by activity measurements and circular dichroism spectroscopy. The results showed that the 308Val substitution decreases protein stability, as compared to the Ile308 variant, an effect also demonstrated during prolonged storage. Ethanol, octanol, 12-hydroxydodecanoic acid and all-trans retinol were used as model substrates and, generally, slightly higher Km values were observed with Val at position 308. Finally, homology modelling, from mouse ADH2, further supported the decreased stability of the Val308 variant and located position 308 in the subunit interface of the molecule and in the vicinity of the active-site pocket entrance. In conclusion, the Ile308Val substitution represents a novel functional polymorphism within the human alcohol dehydrogenase gene cluster that may affect the metabolism of ethanol and other substrates.     

Mental capacity and human consanguinity]

Mental abilities and inbreeding. The comparison between 1,302 adults born from consanguineous marriages underlines a heavy depression of mental abilities. The load of inbreeding equals the load of environment, both adding their influences, without interaction. Homozygosity acts probably more particularly on the brain.