A study was undertaken to explore the content and composition of volatile oil from decaying leaves of lemon-scented eucalypt (Eucalyptus citriodora Hook.) not analyzed earlier. GC and GC-MS analysis of the oil (yield 0.6%) revealed the monoterpenoid nature with citronellal (52.2%), citronellol (12.3%) and isoisopulegol (11.9%) as the major constituents. Overall, 17 components were identified th...

Kinetic properties of regulatory enzymes of glycolysis in liver of the mouse, Zapus hudsonius, were modified during hibernation, the probable mechanism being covalent modification. Liver glycogen phosphorylase activity was strongly depressed during both short (less than 24 h) and long (5-8 days) term hibernation, the mechanism involving a decrease in both the percentage of enzyme in the active ...

The peripheral high-affinity cyclic AMP phosphodiesterase from rat liver plasma membranes was purified to apparent homogeneity. The procedure used involved the initial purification of liver plasma membranes and the solubilization of the enzyme by using a high-ionic-strength medium. This was followed by chromatography of the enzyme on DEAE-cellulose, Affi-Gel Blue, a novel affinity column and Se...

Although insulin effectively blocked hormone-stimulated glycerol output in adipocytes or phosphorylase activation in hepatocytes, the inhibitory effect of insulin on cAMP analog-stimulated cells depended on the cAMP analog used. Of the 20 analogs tested in adipocytes and 13 tested in hepatocytes, the effects of about half of them were effectively blocked by insulin, whereas the effects of many ...

The in vitro and in vivo effects of some drugs on rat erythrocytes 6-phosphogluconate dehydrogenase were investigated in this study. Rat erythrocyte 6-phosphogluconate dehydrogenase was partially purified with ammonium sulfate precipitation. The enzyme activity was determined by Beutler's method. Some drugs such as ampicillin, amikacin sulfate, and netilmicin sulfate inhibited the enzyme activi...

Salicylhydroxamic acid inhibited the luminol-dependent chemiluminescence of human neutrophils stimulated by phorbol 12-myristate 13-acetate or the chemotactic peptide N-formylmethionyl-leucyl-phenylalanine (fMet-Leu-Phe). This compound had no inhibitory effect on the kinetics of O2.- generation or O2 uptake during the respiratory burst, but inhibited both the peroxidative activity of purified m...

Neuropathy target esterase (NTE) is a membrane-bound carboxylesterase activity which is proposed as the target site in nerve tissue for initiation of organophosphate-induced delayed neuropathy. This activity is identified as phenyl valerate hydrolysis which is resistant to treatment with paraxon and sensitive to co-incubation with paraxon and mipafox. NTE preparations were obtained, which did n...

Amperometric hydrogen peroxide enzyme inhibition biosensors based on horseradish peroxidase (HRP) immobilised on electropolymerised neutral red (NR) or directly on the surface of carbon film electrodes (CFE) have been successfully applied to the determination of toxic Cr(III) and Cr(VI). Parameters influencing the performance of the biosensor including the enzyme immobilisation method, the amou...

Human peripheral blood polymorphonuclear leukocytes (PMNs) metabolized [14C]arachidonic acid predominantly by lipoxygenase pathways. The major products were 5-hydroxy-6,8,11,14-eicosatetraenoic acid (5-HETE) and 15-HETE. These and other lipoxygenase products, including their derived leukotrienes, have been implicated as mediators of inflammatory and allergic reactions. In human platelets, the n...