Tyramine-H3: deaminated metabolites in neuroblastoma tumors and in continuous cell line of a neuroblastoma

Neuroblastoma tumors, as well as cultured cells of neuroblastoma, contain high monoamine oxidase activity. The major deaminated metabolite of tyramine-H(3) in the incubation mixtures with the tumors or with the cultured cells is p-hydroxyphenylacetaldehyde. Upon addition of reduced nicotinamide-adenine dinucleotide phosphate, the aldehyde was further metabolized by the reductive pathway to p-hydroxyphenylethanol, whereas upon addition of nicotinamide-adenine dinucleotide phosphate the aldehyde was only metabolized to a minor extent by the oxidative pathway to p-hydroxyphenylacetic acid. Aldehyde dehydrogenase activity is very low in the neuroblastoma tumors and in the cultured neuroblastoma cells. The generation of aldehydes and alcohols by the action of monoamine oxidase suggests that the deaminated metabolites of biogenic amines might exhibit some toxic effects in neuroblastoma patients.     

Microsomal N-demethylation, by a cotton leaf oxidase system, of 3-(4'-chloropENYL)-1, 1-dimethylurea (monuron)

A cotton leaf microsomal oxidase system that N-demethylates 3-(4'-chlorophenyl)-1,1-dimethylurea (monuron) to 3-(4'-chlorophenyl)-1-methylurea has been partially characterized. The enzyme system is associated with a microsomal fraction separated by differential centrifugation and requires molecular oxygen as well as either the reduced form of nicotinamide adenine dinucleotide phosphate or the reduced form of nicotinamide adenine dinucleotide as cofactors.     

Lead effects on corn mitochondrial respiration

Oxidation of exogenous nicotinamide-adenine dinucleotide and succinate by corn mitochondria was measured as a function of lead chloride concentration. Lead chloride (50 to 62 micromoles per liter) stimulated oxidation of exogenous reduced nicotinamide-adenine dinucleotide by 174 to 640 percent depending on the reaction mediums, whereas lead chloride (12.5 micromoles per liter) inhibited succinate oxidation by more than 80 percent. When inorganic phosphate was included in reaction mediums the subsequent addition of lead was without effect due to the low solubility of lead phosphate. If addition of lead was followed by addition of phosphate the inhibition of succinate oxidation by lead was released, but there was no reduction in the stimulation of oxidation of reduced nicotinamide-adenine dinucleotide by lead. The effects of lead on plant growth might be accentuated under conditions of phosphate deficiency.     

Deficiency of reduced nicotinamide-adenine dinucleotide oxidase in chronic granulomatous disease

Reduced nicotinamide-adenine dinucleotide oxidase of normal human polymorphonuclear leukocytes has properties that would qualify it as the enzyme responsible for the respiratory burst during phagocytosis. The enzyme was deficient in leukocytes of five patients with chronic granulomatous disease. This lack of adequate reduced nicotinamide-adenine dinucleotide oxidase could be the basis for the metabolic abnormalities characteristic of these leukocytes and for their diminished bactericidal activity.     

Destruction of cytochrome P 450 by secobarbital and other barbiturates containing allyl groups

Administration of certain commonly used barbiturates containing allyl groups, such as secobarbital, allobarbital, or aprobarbital to rats treated chronically with a microsomal enzyme inducer causes a rapid destruction of the liver microsomal hemoprotein that serves as the terminal oxidase for drug metabolism. In contrast, barbiturates without an allyl group do not have this effect. The decrease in this hemoprotein, cytochrome P(450), by the barbiturates containing an allyl group could also be demonstrated in an in vitro liver microsomal system requiring reduced nicotinamide adenine dinucleotide phosphate. These results suggest that the barbiturates containing an allyl group are converted to a metabolite that leads to the destruction of cytochrome P(450).     

Insulin secretion from toadfish islet tissue stimulated by pyridine nucleotides

The addition of glucose stimulated release of insulin from the isolated islet tissue of the toadfish incubated in vitro. Reduced nicotinamide-adenine dinucleotide also stimulated insulin release, whereas the oxidized form had no effect. Both oxidized and reduced nicotinamide-adenine dinucleatide phosphate stimulated insulin release, but the reduced form was significantly more effective.     

Pyrazole and induction of fatty liver by a single dose of ethanol

Pyrazole (4 millimoles per kilogram or 272 milligrams per kilogram of body weight), given to fasted rats 10 minutes before gavage with ethanol (4 grams per kilogram), completely prevented both the disappearance of ethanol from the blood over a 16-hour period and the ethanol-induced reduction in the ratio of oxidized to reduced hepatic nicotinamide-adenine dinucleotide. However, it did not affect the accumulation of triglycerides in the liver after the administration of ethanol. These results indicate that metabolism of ethanol is not required for production of fatty liver by a single, large dose of ethanol.     

Metabolism of rotenone in vitro by tissue homogenates from mammals and insects

Hydroxylation of rotenone in vitro in the enzyme system composed of microsomes and reduced nicotinamide-adenine dinucleotide phosphate, and in living mice and houseflies, yields products tentatively identified as rotenolone I; rotenolone II; 8'-hydroxyrotenone; 6',7'-dihydro-6',7'-dihydroxyrotenone; two rotenolones of each of the last-mentioned two compounds; and uncharacterized polar materials. The toxicity of certain of these rotenoids to mice is of the same order as that of rotenone.     

Methylene-C14-dioxyphenyl compounds: metabolism in relation to their synergistic action

The methylene-C(14) group is hydroxylated yielding formate-C(14) in the microsome-reduced nicotinamide-adenine dinucleotide phosphate system in vitro and yielding expired C(14)O(2), in living mice and houseflies. Methylenedioxyphenyl compounds apparently serve as alternate substrates for this enzymatic hydroxylation system of microsomes, and thus reduce the rate of metabolism and prolong the action of certain drugs and insecticide chemicals.     

Aryl hydrocarbon (benzopyrene) hydroxylase is stimulated in human lymphocytes by mitogens and benz(a)anthracene

A mixed-function oxidase that requires reduced nicotinamide adenine dinucleotide phosphate, is carbon monoxide sensitive, and is drug-metabolizing is present in human lymphocytes and is increased to different levels by treatment with phytohemagglutinin, pokeweed mitogen, and a polycyclic hydrocarbon.     

Hexokinase isoenzymes in human erythrocytes

The electrophoretic mobility of hexokinase from human erythrocytes and other tissues was studied with a new method that depends on the fluorescence of reduced nicotinamide-adenine dinucleotide phosphate for detecting enzyme activity on starch gel. The hexokinase of cord-blood erythrocytes has slightly different electrophoretic properties from that of adult red cells. Type I enzyme is split into type I(A) and type I(F); the latter is more intense in cord blood; in hemolyzates of adult blood, the activity of the two bands is usually about equal. No type II enzyme was found in cord blood. The double type I band was present in red cells from adult rabbits.     

D(-)-lactate dehydrogenase in lower fungi

A lactate dehydrogenase, specific for nicotinamide-adenine dinucleotide and D(-)-lactate, has been detected in extracts from two fungi of the order Leptomitales (Oomycetes). Several fungi of this order carry out a lactic acid fermentation under conditions of reduced oxygen tension.     

Nicotinamide-adenine dinucleotide in tubercle bacilli exposed to isoniazid

There is a decrease in the content of nicotinamide-adenine dinucleotide of tubercle bacilli grown in the presence of isoniazid. In extracts of tubercle bacilli, the activity of nicotinamide-adenine dinucleotidase is nil or very small; after incubation with the drug the enzyme becomes active. Isoniazid also increases the activity of the enzyme after it is partially activated by heating. There may be a correlation between the capacity of isoniazid to activate the enzyme and the decrease in the dinucleotide content of the tubercle bacilli.     

Alcohol dehydrogenase of Drosophila: interconversion of isoenzymes

Isoenzymes of alcohol dehydrogenase extracted from Drosophila melanogaster are interconvertible and can be distinguished by electrophoretic mobility. When adsorbed on diethylaminoethyl cellulose, the faster-moving forms are converted to the slowest-moving form; the latter is converted to the former in the presence of 0.05 molar nicotinamide-adenine dinucleotide, and the conversion is accompanied by the binding of 3.5 moles of the dinucleotide per mole of enzyme. A change in heat stability accompanies the conversion of the slowest form of alcohol dehydrogenase to the fastest form; the latter becomes stable at 45 degrees C. The increased heat stability may indicate that a conformational change in the alcohol dehydrogenase occurs along with the binding of nicotinamide-adenine dinucleotide.     

Two cytosolic neutrophil oxidase components absent in autosomal chronic granulomatous disease

Neutrophils kill microorganisms with oxygen radicals generated by an oxidase that uses the reduced form of nicotinamide adenine dinucleotide phosphate (NADPH) as substrate. This system requires both membrane and cytosolic components and is defective in patients with chronic granulomatous disease. A cytosolic complex capable of activating latent membrane oxidase was eluted from guanosine triphosphate-agarose and was used to raise polyclonal antiserum that recognized 47- and 67-kilodalton proteins. These proteins were restricted to the cytosol of myeloid cells. Both proteins were associated with NADPH oxidase-activating capacity when neutrophil cytosol was purified on nucleotide affinity matrices or molecular sizing columns. Neutrophils from patients with two different forms of autosomal chronic granulomatous disease lacked either the 47- or 67-kilodalton protein.     

Force, shortening, and work in muscular contraction: relative contributions to overall energy utilization

The amounts of energy used during muscular contraction under different loads have been compared by measurement of the total amount of disturbance of the concentration of reduced nicotinamide-adenine dinucleotide during the period of oxidative recovery. The results are in quantitative agreement with the concept that three parameters determine the energy utilization: namely the time-integral of the force development, the time-integral of the shortening process, and the mechanical work.     

A mammalian H+ channel generated through alternative splicing of the NADPH oxidase homolog NOH-1

Voltage-gated proton (H+) channels are found in many human and animal tissues and play an important role in cellular defense against acidic stress. However, a molecular identification of these unique ion conductances has so far not been achieved. A 191-amino acid protein is described that, upon heterologous expression, has properties indistinguishable from those of native H+ channels. This protein is generated through alternative splicing of messenger RNA derived from the gene NOH-1 (NADPH oxidase homolog 1, where NADPH is the reduced form of nicotinamide adenine dinucleotide phosphate).     

Ketamine-induced loss of phenotype of fast-spiking interneurons is mediated by NADPH-oxidase

Abuse of the dissociative anesthetic ketamine can lead to a syndrome indistinguishable from schizophrenia. In animals, repetitive exposure to this N-methyl-d-aspartate-receptor antagonist induces the dysfunction of a subset of cortical fast-spiking inhibitory interneurons, with loss of expression of parvalbumin and the gamma-aminobutyric acid-producing enzyme GAD67. We show here that exposure of mice to ketamine induced a persistent increase in brain superoxide due to activation in neurons of reduced nicotinamide adenine dinucleotide phosphate (NADPH) oxidase. Decreasing superoxide production prevented the effects of ketamine on inhibitory interneurons in the prefrontal cortex. These results suggest that NADPH oxidase may represent a novel target for the treatment of ketamine-induced psychosis.     

Physiological concentrations of lactate dehydrogenases and substrate inhibition

Lactate dehydrogenases at physiological concentrations are inhibited by high concentrations of pyruvate when the enzyme and the pyruvate are incubated in the presence of oxidized nicotinamide-adenine dinucleotide before assay. The inhibition is much more pronounced with the H-type than with the M-type lactate dehydrogenase. These results suggest that substrate inhibition may be operative in vivo.     

A direct role for dual oxidase in Drosophila gut immunity

Because the mucosal epithelia are in constant contact with large numbers of microorganisms, these surfaces must be armed with efficient microbial control systems. Here, we show that the Drosophila nicotinamide adenine dinucleotide phosphate (NADPH) oxidase enzyme, dual oxidase (dDuox), is indispensable for gut antimicrobial activities. Adult flies in which dDuox expression is silenced showed a marked increase in mortality rate even after a minor infection through ingestion of microbe-contaminated food. This could be restored by the specific reintroduction of dDuox, demonstrating that this oxidase generates a unique epithelial oxidative burst that limits microbial proliferation in the gut. Thus, oxidant-mediated antimicrobial responses are not restricted to the phagocytes, but rather are used more broadly, including in mucosal barrier epithelia.