Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.14.16.2 (tyrosine hydroxylase)
 14,760 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cultured human neuroblastoma cell lines were assayed for biochemical characteristics of neuonal function. Cell lines studied included LA-N-1, LA-N-2, IMR-32, SK-N-SH, and SK-N-MC. Veratridine-dependent uptake of 22Na+ implied the presence of the action potential Na+ ionophore in LA-N-1, LA-N-2, IMR-32, and SK-N-SH. The time course of 22Na+ uptake and inhibition of uptake by tetrodotoxin supported this. SK-N-MC had no veratridine-dependent 22Na+ uptake. Tyrosine hydroxylase (EC 1.14.10.), glutamic acid decarboxylase (EC 4.1.1.15), and acetylcholine contents in neuroblastoma cells were compared to those in brain. LA-N-1 and IMR-32 contained 15 and 5 times as much tyrosine hydroxylase, respectively, whereas LA-N-2, SK-N-SH, and SK-N-MC contained only 0.5 to 5% of that in brain. Acetylcholine was present in -LA-N-2 in 15- to 20-fold greater quantities than in brain; other lines had only 10 to 50% of that in brain. None of the cell lines contained glutamic acid decarboxylase. Thus, continuously propogated human neuroblastoma cell lines may have the action potential Na+ ionophore and may be adrenergic (LA-N-1 and IMR-32), cholinergic (LA-N-2), or inactive (SK-N-SH and SK-N-MC). This is the first demonstration of the action potential Na+ ionophore and of acetylcholine production in human neuroblastoma cell lines.
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PMID:Adrenergic, cholinergic, and inactive human neuroblastoma cell lines with the action-potential Na+ ionophore. 1 22

1. Activity of peripheral and central catecholaminergic neurons was studied in spontaneously hypertensive rats (SHR) and deoxycorticosterone (DOCA)-salt hypertensive rats. 2. In young SHR (4 weeks) the plasma values of bpth noradrenaline and dopamine-beta-hydroxylase activity were increased compared with those of normotensive rats of the Wistar/Kyoto strain. Total catecholamines (mostly adrenaline) were not significantly different. 3. In the adrenal glands of 2-weeks-old and 4-weeks-old SHR activities of tyrosine hydroxylase, dopamine-beta-hydroxylase, phenylethanolamine-N-methyl transferase were decreased, compared to Wistar/Kyoto rats. 4. The adrenaline-forming enzyme was elevated in the A1 and A2 regions of the brain stem of 4-weeks-old SHR and in the A1 region of adult DOCA-salt hypertensive rats. 5. In the adrenal glands of adult DOCA-salt hypertensive rats tyrosine hydroxylase activity was increased. 6. These results implicate peripheral noradrenaline-containing neurons and central adrenaline-containing neurons in the development of genetic and experimental hypertension in rats.
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PMID:Peripheral and central catecholaminergic neurons in genetic and experimental hypertension in rats. 1 56

Tyrosine hydroxylase, dopa oxidase, and peroxidase activities were studied in soluble fractions of B16 melanoma tumor homogenates by polyacrylamide gel disc electrophoresis. Stained gels were scanned photometrically and gel slices were assayed radiometrically. In these preparations, the two bands of tyrosine hydroxylating activity were completely separated from the peroxidase activity but coincided with two major bands of dopa oxidase activity. The third dopa oxidase band coincided with the single band of peroxidase activity. The soluble fraction of cultured cell homogenates had no peroxidase activity, but the two tyrosine hydroxylase bands coincided exactly with the two dopa oxidase bands. Therefore, in the soluble fraction of the murine melanoma bifunctional tyrosinase does exist as two electrophoretically separable forms which are independent of peroxidase.
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PMID:Characteristics of tyrosinase in B16 melanoma. 1 62

A rate of the tyrosine hydroxylase reaction was estimated by an increase in absorption at 335 nm, which was caused by oxidation of pterin cofactor 6,7-dimethyl-5, 6, 7, 8-tetrahydroxypterin (DMPH) coupled with the convertion of the substrate 1-tyrosine into dihydroxyphenylalanine. At pH 6.2 the ratios of molar extinction were as follows: in trisacetate ADMPH4-1370, ADMPH2-5350; in tris-malate tadmph4-1250, admph25300. the enzyme, associated with membranes, had the Km value for Tyr-0.045 mM, the Km for DMPH4 was 0.18 mM; the soluble enzyme had Km for Tyr-0,050 mM, the Km for DMPH4 was 0.74 mM. The stoichiometry of the reaction was 1:1 (I mole DOPA per I mole of DMPH2 formed).
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PMID:[Method for the direct spectrophotometric determination of the rate of the tyrosine hydroxylase reaction]. 1 96

The rat olfactory bulb was studied at the light and electron microscopic level with the indirect immunofluorescence technique and the unlabelled antibody enzyme method (PAP-technique), respectively. Antibodies to all 4 enzymes in the catecholamine synthesis were used. In the principal bulb the first two enzymes, tyrosine hydroxylase (TH) and DOPA decarboxylase (DDC), but not dopamine-beta-hydroxylase (DBH), were present in a proportion of periglomerular cell bodies and dendrites indicating that these neurons synthesize dopamine (DA). This amine may therefore be released as a transmitter substance at some of the intraglomerular dendrodendritic synapses which periglomerular cells form with the mitral cells. There is evidence to suggest that some periglomerular cells use GABA as their transmitter. Thus, a morphologically and physiologically homogenous population of neurons can be subdivided on the basis of transmitter histochemical criteria. There was an impression of more DDC-positive than TH-positive fibers in the glomeruli. Such presumably DDC-positive, but TH-negative processes may represent 5-hydroxytryptamine (5-HT) nerve terminals. DBH-positive fibers were seen in the granular, external plexiform, and very rarely, in the glomerular layers, probably representing noradrenaline (NA) nerve terminals ascending from the lower brain stem. Weakly fluorescent DDC-positive fibers may represent nerve terminals of ascending 5-HT neurons. No phenylethanolamine-N-methyltransferase (PNMT)-positive neurons were observed.
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PMID:Transmitter histochemistry of the rat olfactory bulb. I. Immunohistochemical localization of monoamine synthesizing enzymes. Support for intrabulbar, periglomerular dopamine neurons. 1 85

Stereotaxic injection of 2.5 microng of kainic acid, a rigid analogue of glutamate into the rat striatum caused a 70% reduction in the striatum of the cholinergic parameters, choline acetyltransferase, acetylcholine and synaptosomal uptake of choline and a similar reduction in the GABAergic parameters, glutamic acid decarboxylase, psi-aminobutyric acid (GABA) and synaptosomal uptake of GABA. In contrast, the striatal content of dopamine and the synaptosomal uptake of dopamine were unchanged, and the activity of tyrosine hydroxylase was significantly increased. Significant changes in the activity of neurotransmitter synthesizing enzymes were demonstrable within 6h after injection of 2.5 microng of kainic acid and maximal effects occurred at 48h; the activities of choline acetyltransferase and glutamic acid decarboxylase remained depressed up to 21 days after injection. The kinetic characteristics of striatal tyrosine hydroxylase were altered 48h after injection with a two-fold increase in the Vmax for tyrosine and a three-fold reduction in Km for the pteridine cofactor. In contrast to the effects of kainic acid, the injection of copper sulfate, a non-specific toxin, caused a proportionate reduction in the dopaminergic as well as the cholinergic and GABAergic presynaptic markers. The kainate lesion caused an 85% decrement in the activity of dopamine-sensitive adenylate cyclase, a 40% reduction in the specific binding of [3H]quinuclidinyl benzilate and a 195% increase in the specific binding of [3H]GABA in the striatum. The morphology of the kainate injected striatum was markedly altered with nearly a complete loss of intrinsic neurons, increased number of glial cells but intact internal capsule fibers. Intracerebral injection of nanomolar quantities of kainic acid appears to cause degeneration of neurons with cell bodies near the injection site while sparing axons terminating in or passing through the region.
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PMID:Striatal lesions with kainic acid: neurochemical characteristics. 1 86

Serum dopamine-beta-hydroxylase activity in spontaneously hypertensive rats and Wistar-Kyoto rats had a positive correlation with dopamine-beta-hydroxylase and tyrosine hydroxylase activities in mesenteric vessels, vas deferens, and adrenal glands at 14-16 weeks of age, a negative correlation with dopamine-beta-hydroxylase activity in locus coeruleus at 3 weeks and 14-16 weeks of age, and a positive correlation with tyrosine hydroxylase activity only at 3 weeks of age, but not at 14-16 weeks of age.
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PMID:Correlation between serum dopamine-beta-hydroxylase activity and dopamine-beta-hydroxylase and tyrosine hydroxylase activities in central and peripheral adrenergic neurons and adrenal glands. 1 69

A statistically significant decrease in the intensity of catecholamine fluorescence of some carotid body glomus cells was observed after inhibition of the enzyme tyrosine hydroxylase by injection of 80 mg/kg alpha-methyl-paratyrosine. The intensity of the formaldehyde-induced fluorescence was measured in individual glomus cells. The maximum decrease in the intensity was observed 4 to 6 hr after the alpha-methyltyrosine injection. This suggests a rapid turnover in the catecholamines of the carotid body.
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PMID:Loss of histochemically demonstrable catecholamines in the glomus cells of the carotid body after alpha-methyl-para-tyrosine treatment. 1 34

Bovine adrenal tyrosine hydroxylase has been obtained in a form that is 85 to 90% pure. Sodium dodecyl sulfate-gel electrophoresis and density gradient centrifugation studies have established that the subunit molecular weight of the chymotrypsin-solubilized enzyme is 34,000. The presence of iron in the purified enzyme (0.50 to 0.75 mol of iron/mol of enzyme) has been established. Crude particulate tyrosine hydroxylase can be activated by the phospholipid, phosphatidyl-L-serine, or by exposure to enzymatic phosphorylating conditions. Both forms of activation lower the Km of the enzyme for its 2-amino-4-hydroxypteridine cofactor. By contrast, tyrosine hydroxylase that has been solubilized by chymotrypsin cannot be activated by either of these methods.
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PMID:Bovine adrenal tyrosine hydroxylase: purification and properties. 1 85

Nigral basal adenylate cyclase and dopamine-sensitive adenylate cyclase, glutamate decarboxylase, choline acetyltransferase, and tyrosine hydroxylase activities were measured in rats with hemitransections at various levels or with electrolytic lesions of the medial forebrain bundle or the crus cerebri. The loss of nigral dopamine-sensitive adenylate cyclase activity after the various brain lesions was correlated with loss of nigral glutamic acid decarboxylase but not that of tyrosine hydroxylase; nigral choline acetyltransferase was unaffected in all cases. The data indicate that the nigral dopamine-sensitive adenylate cylase activity may be localized on neurons afferent to the nigra, probably originating from the globus pallidus and possibly from the tail of the caudate. The results suggest that dopamine, released from nigral dendrites, may influence dopaminergic activity indirectly by modulating impulses transmitted to the nigrostriatal neurons through the crus cerebri.
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PMID:Localization of nigral dopamine-sensitive adenylate cyclase on neurons originating from the corpus striatum. 1 59


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