Swaraj K. Chattopadhyay

Erythrocyte Abnormality in Human Myopathy

Erythrocyte ghosts isolated from myopathic patients responded to 10-4 molar ouabain with a dramatic increase in adenosine triphosphatase activity, while identical preparations from normal donors were inhibited by the same drug. These results have been interpreted in terms of a disease-related change in membrane integrity bearing upon function of the transport enzyme.

Glycoside effect upon membrane enzymes of erythrocytes and muscle in duck myopathy

Skelettmuskelmembrane und Erythrozytenstromata normaler Enten zeigen eine adenosine triphosphatase Aktivität, die durch das herzaktive Glykosid Ouabain gehemmt wird. Das gleiche Material von Enten mit Myopathien zeigte eine durch Ouabain stimulierte ATPase-Aktivität.

Effect of sodium fluoride on the epinephrine response of liver and hepatoma adenyl cyclase.

Die in vitro Stimulation der Adenyl-Cyclase durch Epinephrin zur Bildung der zyklischen AMP ist im Hepatomgewebe signifikant höher als in der normalen Rattenleber. Sodiumfluorid hemmt in beiden Fällen die Stimulation.

Glucagon Stimulation of Adenyl-Cyclase Activity of Cardiac Muscle

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Preparation and properties of matrix-supported horseradish peroxidase.

A new method of enzyme immobilization has been described using poly(4-methacryloxybenzoic acid) as the carrier. Activation of the polymer, prior to enzyme attachment, was achieved with N-ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline. The enzyme coupling step proceeded through nucleophilic attack by the protein on a mixed carbonic anhydride. The degree of polymer activation was determined by analysis for quinoline, a by-product of the reaction. The polymer-enzyme complex was compared to the enzyme in solution in terms of pH optimum, substrate kinetics, and thermal denaturation. Potential uses of the polymerenzyme system in chemical synthesis of benzoquinone derivatives are discussed.

Analytical Application of Microcalorimetry

Abstract A “bench top” microcalorimeter has been designed and constructed. This instrument, and a more conventional microcalorimeter previously described, have been applied to several analytical determinations including both inorganic and enzymatic reactions. Because of the stability, yet rapid equilibration time of the bench top calorimeter, multiple analyses may be performed. The ease of operation, nearly universal applicability, and the possibility of obtaining thermodynamic as well as kinetic data simultaneously, make this technique extremely useful.

l-Asparaginase activity in several mammalian species

Abstract 1. 1. l -Asparaginase activities derived from the cytoplasmic fraction of the liver of several species have been compared. 2. 2. Parameters considered were substrate affinity, stability, p H, and temperature optima. p H optima for each species were identical with a relatively broad range of 7.5–8.6. Temperature optimum was 37° C. 3. 3. K m values for the calf ( Bos longifrons ), guinea-pig ( Caoia cobaya ), Jax DBA mouse ( Mus musadus ), and Buffalo rat ( Rattus norvegicus ) enzyme preparations arc 9.3 × 10 −3 , 8.7× 10 −3 , 1.0 × 10 −3 , and 4.9 × 10 −3 respectively. Stability of the several preparations was similar. 4. 4. By the fourth day of storage at 4°C., 46 per cent of the l -asparaginase activity had been lost in the calf, guinea-pig, and mouse; 41 per cent was lost in Buffalo rat preparations. Activity level and substrate affinities varied widely. This is discussed.

CO-binding pigment (P-450) and other electron transport components in hepatoma bearing rats

Basierend auf früheren Eiweissuntersuchungen bezüglich einer endoplasmatisch-retikulären Elektronenstromkette ergibt sich: NADPH-Oxydase und Zytochrom-c-Reduktase sind in der normalen Rattenleber wie in der Hepatoma (Typ 7777) tragenden gleich, während die Ferricyanid-Reduktase und P-450 in der Leber der letzteren herabgesetzt waren.

Detergent solubilization of NADPH oxidase

Abstract 1. 1. The study was designed to provide a basis for the choice of a solubilization technique, which would allow the isolation of endoplasmic reticulum NADPH oxidase (E.C. 1.6.99.2). 2. 2. Digitonin, Lubrol, Poly-tergent, butanol, sonication and snake venom phospholipase were used over a range of concentrations and conditions. 3. 3. NADPH oxidase activity was most effectively solubilized using 0.3 per cent Lubrol. 4. 4. The preparation had a specific activity of 4.2 nmoles per minute per mg. protein. The NADPH oxidase activity resided with particles having molecular dimensions of 0.1.–0.25 μm. diameter. 5. 5. Electron microscopy and the enzyme d -amino-acid oxidase, used as a marker, indicated that these structures are peroxisomes. 6. 6. Lubrol and Poly-tergent, both non-ionic detergents, are useful for the isolation of NADPH oxidase activity.

A note on supporting matrices for adenyl cyclase.

Abstract Five insoluble matrices are described for the solid-support of solubilized cardiac adenyl cyclase. Straight forward chemistries are proposed for the reactions involved and for at least one matrix, an apparent purification of the cyclase activity was observed.