We have found that cytoplasmic extracts from unfertilized sea-urchin eggs contain a prominent microtubule-activated ATPase activity. This activity is induced by polymeric tubulin, but not by tubulin subunits. The activity cosediments with taxol-stabilized microtubules in an ATP-independent manner. We have separated the ATPase from cytoplasmic dynein and other ATPases on sucrose gradients. The s...

NAD+ glycohydrolase (NADase; EC 3.2.2.5) is an enzyme that catalyses hydrolysis of NAD+ to produce ADP-ribose and nicotinamide. Its physiological role and the regulation of its enzymic activity have not been fully elucidated. In the present study, the mechanism of self-inactivation of NADase by its substrate, NAD+, was investigated by using intact rabbit erythrocytes and purified NADase. Our re...

Human Cytochrome P450 2J2 (CYP2J2) as an important metabolic enzyme, plays a crucial role in metabolism of polyunsaturated fatty acids (PUFAs). Elevated levels CYP2J2 have been associated with various types cancer, and therefore it serves potential drug target. Herein, using high-throughput screening approach based on enzymic activity CYP2J2, we rapidly effectively identified novel natural inhi...

It has been previously demonstrated that the enzymic activity of rat liver 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMG-CoA reductase; EC 1.1.1.34) is modulated in vitro and in vivo by a bicyclic cascade system involving reversible phosphorylation of HMG-CoA reductase and reductase kinase. In the present study, administration of mevalonolactone to rats caused a rapid inhibition of HMG-C...

NAD+ glycohydrolase (NADase) and non-enzymic ADP-ribosylation have been thought to be involved in the regulation of mitochondrial Ca2+ fluxes. In this study it was found that several conditions (5 mM nicotinamide, 5 mM 3-aminobenzamide, 2 mM EDTA, 1 mM ATP, 10 mM dithiothreitol) known to strongly inhibit the NADase decreased ADP-ribosylation in bovine liver mitochondrial membranes with [32P]NAD...

with 50 % (v/v) ethanol and radioactivity determined by liquid-scintillation counting. The separation procedure used is capable of separating cyclic AMP from all known naturally occurring adenine nucleotides. Results showed that the ‘total‘ membrane fraction from barley leaves possesses adenylate cyclase activity equivalent to 26pmol of cyclic AMP formed/min per mg of membrane protein. The lOOO...

Uricase from Candida species was immobilized covalently onto the inner wall of a plasticized polyvinyl chloride (PVC/plastic) vial through glutraldehyde coupling with a 65.23% retention of its initial activity and a conjugation yield of 0.37 mg/cm(2). The vial-bound enzyme showed the optimum activity at pH 7.2, when incubated at 45°C for 5 min. There was a linear relationship between the immobi...

The oxidation of protoporphyrinogen IX to protoporphyrin TX in yeast cells is enzyme-dependent. The enzyme, protoporphyrinogen oxidase, associated with purified mitochondria isolated from Saccharomyces cereuisiae was solubilized by sonic treatment in the presence of detergent and partially purified. The molecular weight of the enzyme was 180,000 f 18,000. The purified preparation could be store...

1. Na+,K(+)-ATPase is the membrane enzyme catalysing the active transport of Na+ and K+ across the plasma membrane of animal cells. A reduced activity of Na+,K(+)-ATPase has been described in gestational hypertension in a variety of cell types, in agreement with the hypothesis that gestational hypertension can induce membrane transport modifications similar to those reported for essential hyper...

A poly(ADP-ribose) polymerase-like enzyme, detected in a crude homogenate from Sulfolobus solfataricus by means of activity and immunoblot analyses, was purified to electrophoretic homogeneity by a rapid procedure including two sequential affinity chromatographies, on NAD+-agarose and DNA-Sepharose. The latter column selected specifically the poly(ADP-ribosyl)ating enzyme with a 17% recovery of...