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PubMed1986

Effects of an antitumoural rhodium complex on thioacetamide-induced liver tumor in rats. Changes in the activities of ornithine decarboxylase, tyrosine aminotransferase and of enzymes involved in fatty acid and glycerolipid synthesis.

Rats were injected daily for 8 weeks with 50 mg of thioacetamide per kg to produce liver tumours. Some of these rats were given three doses of 50 mg of an antitumoural Rh(III) complex/kg at 14, 9 and 5 days before the end of the thioacetamide treatment. Thioacetamide decreased the rate of weight gain of the rats and the Rh(III) complex partly restored it. The activities of ATP citrate lyase, acetyl-CoA carboxylase and fatty acid synthetase in the livers were decreased by thioacetamide treatment and the Rh(III) complex partly reversed this effect. By contrast the activity of malic enzyme was increased by both thioacetamide and the Rh(III) complex and this effect probably relates to NADPH production for detoxification rather than for lipogenesis. Treatment with thioacetamide increased the rate of synthesis of di- and triacylglycerols from glycerol phosphate by liver homogenates, the activity of phosphatidate phosphohydrolase and the incorporation of [3H]glycerol into liver triacylglycerol in vivo. The Rh(III) complex did not produce a significant reversal of these effects of thioacetamide on glycerolipid synthesis. The total uptake of intraportally injected [3H]glycerol by the livers of thioacetamide treated rats was decreased and this was associated with a lowered activity of glycerol kinase. Thioacetamide increased the activity of hepatic ornithine decarboxylase by about 40-fold, but the Rh(III) complex did not reverse this effect. However, the decrease in tyrosine aminotransferase activity that was produced by thioacetamide was partly reversed by the Rh(III) complex. These results are discussed in relation to the tumour-promoting effects of thioacetamide and the antitumoural action of the Rh(III) complex.

ATP Citrate (pro-S)-Lyase↗
PubMed1990

Assays for amino acid decarboxylase enzymes using ion-exchange cartridges.

A general radiochemical method for estimating the activity of amino acid decarboxylases is reported. This method utilizes ion-exchange cartridges to separate unreacted radiolabeled amino acid substrates from product amines, which can then readily be quantitated by liquid scintillation counting. The assay is simple, rapid, and more sensitive than standard 14CO2 trapping procedures if uniformly labeled amino acid substrates are utilized. Acidic, basic, and aromatic amino acid decarboxylases can be assayed with the appropriate choice of cation or anion exchangers. The utility of the method is demonstrated for aspartate-alpha-decarboxylase, tyrosine decarboxylase, and lysine decarboxylase where kinetic parameters are comparable to values obtained by standard radiochemical 14CO2 trapping assays.

Amino Acids↗
PubMed1980

Effect of pyridoxal 5-phosphate on carbidopa and decarboxylation of levodopa.

To study the interaction between enzymes and coenzymes and carbidopa and levodopa, a paired-ion high-pressure liquid chromatographic method was developed to separate carbidopa, dopamine, levodopa, and pyridoxal 5-phosphate. Carbidopa strongly reacted with pyridoxal 5-phosphate, contrary to a previous report. Tyrosine decarboxylase and tyrosine decarboxylase apoenzyme had some activity against levodopa, which could be increased by adding pyridoxal 5-phosphate to the mixture. This activity was inhibited by hydroxylamine hydrochloride.

Apoenzymes↗
PubMed2005

Tyramine Functions independently of octopamine in the Caenorhabditis elegans nervous system.

Octopamine biosynthesis requires tyrosine decarboxylase to convert tyrosine into tyramine and tyramine beta-hydroxylase to convert tyramine into octopamine. We identified and characterized a Caenorhabditis elegans tyrosine decarboxylase gene, tdc-1, and a tyramine beta-hydroxylase gene, tbh-1. The TBH-1 protein is expressed in a subset of TDC-1-expressing cells, indicating that C. elegans has tyraminergic cells that are distinct from its octopaminergic cells. tdc-1 mutants have behavioral defects not shared by tbh-1 mutants. We show that tyramine plays a specific role in the inhibition of egg laying, the modulation of reversal behavior, and the suppression of head oscillations in response to anterior touch. We propose a model for the neural circuit that coordinates locomotion and head oscillations in response to anterior touch. Our findings establish tyramine as a neurotransmitter in C. elegans, and we suggest that tyramine is a genuine neurotransmitter in other invertebrates and possibly in vertebrates as well.

Amino Acid Sequence↗
PubMed1983

Decarboxylation of p-tyrosine: a potential source of p-tyramine in mammalian tissues.

The question of the existence of a p-tyrosine decarboxylase pathway for the formation of p-tyramine in mammalian tissues remains unresolved. Development of a sensitive and specific assay for p-tyrosine decarboxylase has permitted demonstration of this activity in rat tissues and human kidney. Tyrosine decarboxylase was purified to electrophoretic homogeneity by pH 5.0 precipitation, ammonium sulfate precipitation, gel filtration, phenyl-Sepharose chromatography, DEAE-Sephacel chromatography, and preparative isoelectric focusing. A specific rabbit antiserum to tyrosine decarboxylase was also obtained. Purified tyrosine decarboxylase possessed a narrow pH dependency with an optimum at 8.0. Benzene and certain other organic solvents dramatically stimulated tyrosine decarboxylase activity of purified enzyme. Purified tyrosine decarboxylase activity also decarboxylated L-DOPA, 5-hydroxytryptophan, 3,4-dihydroxyphenylserine, o-tyrosine, m-tyrosine, phenylalanine, histidine, and tryptophan, which suggested that the purified enzyme was aromatic L-amino acid decarboxylase. This conclusion was supported by a constant ratio of 5-hydroxytryptophan decarboxylase to tyrosine decarboxylase throughout the purification scheme and by parallel immunoprecipitation of decarboxylase activities by the specific antityrosine decarboxylase antisera. Thus, we report that p-tyrosine is decarboxylated by aromatic L-amino acid decarboxylase and that this metabolic transformation may be an important source of p-tyramine in mammalian tissues. In conclusion, neuronal tissues that synthesize catecholamines or serotonin should now be considered capable of synthesizing p-tyramine and other biogenic amines.

Animals↗
PubMed1996

Relation of ornithine decarboxylase and tyrosine kinase activity in the jejunal mucosa in vivo.

Our aim was to study the relationship between jejunal mucosal activity of ornithine decarboxylase and tyrosine kinase during proliferation in adolescent rats in vivo. Their relationship in the proliferating intestinal mucosa under in vivo conditions has not been reported before. From the results of in vitro studies, it was speculated that tyrosine kinase activity modulated ornithine decarboxylase activity during colonic mucosal proliferation (Majumdar AP. Am J Physiol 259:G626-G630, 1990). Jejunal mucosal hyperplasia was induced by Type 1 diabetes and suppressed in both control and diabetic rats by administration of difluoromethylornithine. Jejunal mucosal weight and enzyme activity were determined after 3, 6, and 10 days, and tyrosine-specific phosphorylated proteins after 10 days of induction of diabetes. Difluoromethylornithine suppressed jejunal mucosal proliferation and tyrosine kinase activity after the 6- and 10- day study periods. After the 3-day study period although jejunal mucosal growth was suppressed, tyrosine kinase activity was not. Activity of tyrosine kinase and ornithine decarboxylase were highly significantly correlated at all time periods in both control and diabetic rats. Tyrosine-specific phosphorylated proteins of 34, 54, 80, and 200 kDa proteins were observed in jejunal mucosa of both control and diabetic rats. In the difluoromethylornithine-treated rats, phosphorylation of the above proteins was negligible while the phosphorylation of a 14-kDa protein was prominent. We speculate that in vivo ornithine decarboxylase activity may be modulating tyrosine kinase activity and that phosphorylation of a 14-kDa protein was associated with suppressed mucosal growth in difluoromethylornithine-treated rats.

Animals↗
PubMed1997

Effect of pinealectomy, superior cervical ganglionectomy, or melatonin treatment on 24-hour rhythms in ornithine decarboxylase and tyrosine hydroxylase activities of rat spleen.

Diurnal variations in splenic ornithine decarboxylase and tyrosine hydroxylase activities were examined in rats subjected to pinealectomy, bilateral superior cervical ganglionectomy, or their respective sham operations. Rats were treated with Freund's complete adjuvant or its vehicle 2 days before sacrifice. After immunization, splenic ornithine decarboxylase activity was augmented 5-6-fold. In both immunized and nonimmunized sham-operated rats, significant diurnal variations in ornithine decarboxylase activity were detectable, with a maximum at early morning, acrophases after Cosinor analysis varying from 0845 to 1048h. In pinealectomized or superior cervical ganglionectomized, immunized rats, ornithine decarboxylase activity attained values 22-27% lower than those of immunized sham-operated controls, while amplitude decreased significantly by 27-30%. Administration of melatonin (30 microg/animal s.c. at late evening for 11 days in immunized rats) significantly augmented mesor levels of splenic ornithine decarboxylase activity and increased the amplitude of the diurnal rhythm both in pinealectomized and in superior cervical ganglionectomized rats. Melatonin treatment also augmented rhythm mesor in immunized, sham-ganglionectomized rats, as well as rhythm amplitude in immunized and nonimmunized, sham-ganglionectomized rats. Splenic tyrosine hydroxylase activity attained its maximum at late afternoon and early night, with acrophases varying from 1800 to 2023h. Immunization significantly increased mesor values of splenic tyrosine hydroxylase activity, whereas neither pinealectomy nor superior cervical ganglionectomy affected circadian rhythm parameters. Melatonin treatment augmented mesor values of tyrosine hydroxylase rhythm and increased its amplitude in pinealectomized, ganglionectomized, or sham-operated rats. The results are compatible with the view that the pineal gland plays a role in circadian changes of immune responsiveness in rat spleen via an immunopotentiating effect of melatonin on splenic cell proliferation.

Animals↗
PubMed2006

Production of biogenic amines by lactic acid bacteria: screening by PCR, thin-layer chromatography, and high-performance liquid chromatography of strains isolated from wine and must.

Biogenic amines are frequently found in wine and other fermented food. We investigated the ability of 133 strains of lactic acid bacteria isolated from musts and wines of different origins to produce histamine, tyramine, and putrescine. We detected the genes responsible for encoding the corresponding amino acid decarboxylases through PCR assays using two primer sets for every gene: histidine decarboxylase (hdc), tyrosine decarboxylase (tdc), and ornithine decarboxylase (odc); these primers were taken from the literature or designed by us. Only one strain of Lactobacillus hilgardii was shown to possess the hdc gene, whereas four strains of Lactobacillus brevis had the tdc gene. None of the Oenococcus oeni strains, the main agents of malolactic fermentation, was a biogenic amine producer. All PCR amplicon band-positive results were confirmed by thin-layer chromatography and high-performance liquid chromatography analyses.

Base Sequence↗
PubMed2002

Stress response in Drosophila melanogaster strain inactive with decreased tyramine and octopamine contents.

Juvenile hormone hydrolysis, tyrosine decarboxylase activity, dopamine content and fitness (viability and fertility) were studied under normal and stress conditions in the adults of Drosophila melanogaster inactive strain carrying a mutation that decreases tyrosine decarboxylase activity and results in the lower contents of tyramine and octopamine. A sexual dimorphism of tyrosine decarboxylase activity, dopamine level and survival under heat stress in inactive flies was found. inactive adults showed higher dopamine levels and lower survival levels under heat stress as compared to wild type (Canton S) adults. Juvenile hormone degradation is decreased in young and increased in mature inactive females as compared to wild type. Fertility of the inactive strain did not differ from that of wild type strain under normal conditions, but after heat exposure the dynamics of its restoration was different. inactive females were found to develop the stress reaction, with juvenile hormone degradation, tyrosine decarboxylase activity, dopamine content and fertility levels used as the reaction indicators.

Animals↗
PubMed1980

Age-related changes in inducible mouse liver enzymes: ornithine decarboxylase and tyrosine aminotransferase.

The time required to induce two inducible hepatic enzymes, ornithine decarboxylase (ODC) and tyrosine aminotransferase (TAT), by growth hormone and dexamethasone, respectively, increases with age. Specific activity at the peak of induction is the same for all ages. On the other hand, for basal TAT the specific activity per unit of TAT antigen was found to decrease considerably with age. The half-life of ODC was determined after cycloheximide administration. The apparent half-life at the peak of ODC induction increases from 15 minutes in 3-4-month-old mice to 30 minutes in 24-month-old animals. Loss of efficiency in the protein degradation system is implicated in this phenomenon as no apparent differences could be observed in the susceptibility of ODC and TAT from young or old mice to chymotrypsin. ODC and TAT are activated by temperatures of up to 37 degrees C and 50 degrees C, respectively. ODC is inactivated at 50 degrees C while TAT is inactivated at 76 degrees C. "Young" ODC and TAT are more readily activated or inactivated by heating than the "old" enzymes.

Aging↗
PubMed1998

The dopaminergic innervation of the pigeon telencephalon: distribution of DARPP-32 and co-occurrence with glutamate decarboxylase and tyrosine hydroxylase.

Dopaminergic axons arising from midbrain nuclei innervate the mammalian and avian telencephalon with heterogeneous regional and laminar distributions. In primate, rodent, and avian species, the neuromodulator dopamine is low or almost absent in most primary sensory areas and is most abundant in the striatal parts of the basal ganglia. Furthermore, dopaminergic fibres are present in most limbic and associative structures. Herein, the distribution of DARPP-32, a phosphoprotein related to the dopamine D1-receptor, was investigated in the pigeon telencephalon by immunocytochemical techniques. Furthermore, co-occurrence of DARPP-32-positive perikarya with tyrosine hydroxylase-positive pericellular axonal "baskets" or glutamate decarboxylase-positive neurons, as well as co-occurrence of tyrosine hydroxylase and glutamate decarboxylase were examined. Specificity of the anti-DARPP-32 monoclonal antibody in pigeon brain was determined by immunoblotting. The distribution of DARPP-32 shared important features with the distribution of D1-receptors and dopaminergic fibres in the pigeon telencephalon as described previously. In particular, DARPP-32 was highly abundant in the avian basal ganglia, where a high percentage of neurons were labelled in the "striatal" parts (paleostriatum augmentatum, lobus parolfactorius), while only neuropil staining was observed in the "pallidal" portions (paleostriatum primitivum). In contrast, DARPP-32 was almost absent or present in comparatively lower concentrations in most primary sensory areas. Secondary sensory and tertiary areas of the neostriatum contained numbers of labelled neurons comparable to that of the basal ganglia and intermediate levels of neuropil staining. Approximately up to one-third of DARPP-32-positive neurons received a basket-type innervation from tyrosine hydroxylase-positive fibres in the lateral and caudal neostriatum, but only about half as many did in the medial and frontal neostriatum, and even less so in the hyperstriatum. No case of colocalization of glutamate decarboxylase and DARPP-32 and no co-occurrence of glutamate decarboxylase-positive neurons and tyrosine hydroxylase-basket-like structures could be detected out of more than 2000 glutamate decarboxylase-positive neurons examined, although the high DARPP-32 and high tyrosine hydroxylase staining density hampered this analysis in the basal ganglia. In conclusion, the pigeon dopaminergic system seems to be organized similar to that of mammals. Apparently, in the telencephalon, dopamine has its primary function in higher level sensory, associative and motor processes, since primary areas showed only weak or no anatomical cues of dopaminergic modulation. Dopamine might exert its effects primarily by modulating the physiological properties of non-GABAergic and therefore presumably excitatory units.

Animals↗
PubMed1985

Evidence for specific immunolysis of nerve terminals using antisera against choline acetyltransferase, glutamate decarboxylase and tyrosine hydroxylase.

Synaptosomes prepared from striatum or cerebral cortex of rat brain were incubated with antibodies raised against three neurotransmitter biosynthetic enzymes, choline acetyltransferase, glutamate decarboxylase and tyrosine hydroxylase in the presence or absence of complement. Immunolysis was first assessed by measuring the release of lactic dehydrogenase or reduction in potassium from synaptosomes, and lysis of neurochemically specific subpopulation of synaptosomes was detected by measuring release of either transmitters, their biosynthetic enzymes or by blockade of sodium-dependent uptake of transmitter or precursor. In both striatum and cortex, antibodies to choline acetyltransferase lysed only cholinergic while those against glutamate decarboxylase only lysed GABAergic nerve terminals. Antibodies against tyrosine hydroxylase lysed only the dopaminergic terminals in striatum but not noradrenergic terminals in cortex. The lysis occurred only in the presence of complement, and was never observed in the absence of complement. The studies indicate that antibodies to the neurotransmitter biosynthetic enzymes recognize antigens in the synaptosomal membrane specific only to neurons harboring the transmitters. The results suggest that the antibody-positive peptides in the membrane and neurotransmitter biosynthetic enzyme share common antigenic sites, probably common peptides.

Animals↗
PubMed2003

[Glutamic acid decarboxylase and tyrosine phosphatase-like IA-2 antibodies for diabetes classification in unselected diabetic patients].

BACKGROUND: The determination of glutamic acid decarboxylase and tyrosine phosphatase-like antibodies (GAD-AB and IA-2-AB) may be useful for the classification of diabetes, and in selected patient groups the measurement of these autoantibodies has been shown to be rather sensitive and specific. PATIENTS AND METHODS: In this study we examined the use of these antibody determination in a clinical setting of 157 diabetic outpatients recruited randomly from our diabetes clinic. The prevalence of the different antibodies was set in relation to the clinically classified diabetes type and to diabetes duration. RESULTS: Among the patients with a clinical diagnosis of type 1 diabetes, the GAD-AB were clearly positive in 44% and borderline positive in 10%, whereas the IA-2-AB were positive or borderline positive in 36% of these patients. The prevalence of positive autoantibodies declined with increasing duration of type 1 diabetes. Among the patients with clinically diagnosed type 2 diabetes, the GAD-AB were clearly positive in 25.2% and borderline positive in 13.1%, IA-2-AB were only found in 4.7%. Patients with a clinical diagnosis of type 2 diabetes but positive for GAD-AB could not clearly be identified as having latent autoimmune diabetes in adults (LADA), since some of them did not need insulin therapy up to 10 years after the diagnosis of diabetes. The prevalence of GAD-AB in type 2 diabetic/LADA patients did not depend on diabetes duration. CONCLUSION: We conclude that the determination especially of GAD-AB may be useful for the classification of diabetes in clinically unclear cases. The additional determination of IA-2-AB appears to provide only limited additional information.

Adult↗
PubMed2006

First genetic characterization of a bacterial beta-phenylethylamine biosynthetic enzyme in Enterococcus faecium RM58.

Enterococcus faecium RM58 produces beta-phenylethylamine and tyramine. A gene from Ent. faecium RM58 coding for a 625 amino-acid residues protein that shows 85% identity to Enterococcus faecalis tyrosine decarboxylase has been expressed in Escherichia coli, resulting in L-phenylalanine and L-tyrosine decarboxylase activities. Both activities were lost when a truncated protein lacking 84 amino acids at its C-terminus was expressed in E. coli. This study constitutes the first genetic characterization of a bacterial protein having L-phenylalanine decarboxylase activity and solves a long-standing question regarding the specificity of tyrosine decarboxylases in enterococci.

Carboxy-Lyases↗
PubMed1997

Reciprocal regulation of the content of aromatic L-amino acid decarboxylase and tyrosine hydroxylase mRNA by NGF in PC12 cells.

Aromatic L-amino acid decarboxylase (AADC) and tyrosine hydroxylase (TH) are involved in the synthesis of dopamine and other monoamine neurotransmitters, and their activities can be regulated by a number of physiological stimuli. An interesting finding has been that (-)-deprenyl and some other irreversible monoamine B oxidase inhibitors increase AADC gene expression and that these compounds can exert neuronal protection/rescue effects. In this study, we have investigated the effects of nerve growth factor (NGF), and of (-)-deprenyl on AADC and TH gene expression in PC12 cells. Cells were treated with different doses of NGF (0.2-50 ng/ml) for up to 3 days. Northern and blot hybridizations were performed to detect AADC and TH mRNA. The results show that NGF can down-regulate AADC gene expression while increasing TH gene expression in a time- and dose-dependent fashion. Treatment with (-)-deprenyl alone increases the gene expression of AADC, and (-)-deprenyl further counteracts the reductions induced by NGF. This study introduces novel results with regard to the regulation of the gene expression of AADC in PC12 cells, which is not paralleled by the other catecholamine biosynthetic enzymes. These findings support the existence of an interaction between NGF and AADC gene expression that may be associated with the process of neuronal degeneration or regeneration.

Animals↗
PubMed1998

Aromatic L-amino acid decarboxylase- and tyrosine hydroxylase-immunohistochemistry in the adult human hypothalamus.

The distribution of cell bodies immunoreactive for tyrosine hydroxylase and aromatic L-amino acid decarboxylase was studied in the adult human hypothalamus. Many neurons in the posterior (A11) and caudal dorsal hypothalamic areas (A13) as well as in the arcuate (A12) and periventricular (A14) zone were immunoreactive for the two enzymes, suggesting that they were dopaminergic. Numerous tyrosine hydroxylase-immunoreactive neurons, which were not immunoreactive for aromatic L-amino acid decarboxylase, could be seen in the paraventricular, supraoptic and accessory nuclei (A15) as well as in the rostral dorsal hypothalamic area. These were considered to be non-dopaminergic. Conversely, large numbers of small neurons immunoreactive for aromatic L-amino acid decarboxylase but not for tyrosine hydroxylase, were identified in the premammillary nucleus (D8), zona incerta (D10), lateral hypothalamic area (D11), anterior portion of the dorsomedial nucleus (D12), suprachiasmatic nucleus (D13), medial preoptic area and bed nucleus of the stria terminalis (D14). In the human hypothalamus, besides dopaminergic cell bodies, there exists a large number of tyrosine hydroxylase-only and aromatic L-amino acid decarboxylase-only neurons, whose physiological roles remain to be determined.

Aged↗
PubMed1976

Choline acetyltransferase, glutamate decarboxylase and tyrosine hydroxylase in the cochlea and cochlear nucleus of the guinea pig.

Activities of choline acetyltransferase (ChAC), glutamate decarboxylase (GAD) and tyrosine hydroxylase (TH), enzymes catalyzing the synthesis of acetylcholine (ACh), gamma-aminobutyric acid (GABA) and catecholamines, respectively, were measured in the cochlea and cochlear nucleus of the guinea pig. ChAc activity in the organ of Corti, third turn, was 1270 pmole ACh formed/min/mg protein (ChAc, 1270) and was higher than in turn 4 (ChAc, 543). ChAc activity was higher when the preparation included the inner hair cell region than when not. GAD activity in samples of turn 3 and 4 combined was low, 0.17 nmole GABA formed/min/mg protein (GAD, 0.17). All 3 enzymes were low in auditory nerve: ChAc, 1.7, GAD, 0.10 and TH, 1.0 pmole DOPA formed/min/mg protein. In the cochlear nucleus, the values were: ChAc, 129, GAD, 1.70 and TH, 2.7. The findings on the distribution of ChAc activity in the organ of Corti fit the hypothesis that the olivocochlear nerve fibers are cholinergic. Because of low GAD in the cochlea, GABA is unlikely to be transmitter in the organ of Corti. Similarly, it is unlikely that ACh, GABA or a catecholamine is a transmitter between the auditory nerve and the cochlear nucleus.

Acetyltransferases↗