Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0027960 (mole)
 21,279 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Junction nevus, dermal nevus, melanosis circumscripta praecancerosa Dubreuilh, superficial spreading melanoma, and nodular melanoma were investigated and characterized by use of the formalin induced fluorescence method (FIF). In the vicinity of junctional nevus cell clusters and near tumor cells of the superficial spreading melanoma increased numbers of melanocytes are found. These show different types of dendritic branching. Spherical nevus cells however are completely devoid of dendritic processes. On the other hand, the atypical pigment cells in melanosis circumscripta praecancerosa Dubreuilh exhibit a shape similar to that of melanocytes, whereas the globular cells of superficial spreading melanoma have the appearance of nevus cells. The arrangement of nodular melanoma cells resembles that observed in dermal nevus. However the characteristic decrease in fluorescence intensity from epidermal junction to deeper dermis as observed in the dermal nevus was missed in nodular melanomas. Dendritic pigment cells displaying formalin induced fluorescence (FIF) could be demonstrated in all types of malignant melanomas investigated in the present study. The fluorophores of the pigment lesions are characterized microspectrofluorimetrically by (1) ill-defined emission maxima between 470 and 490 nm and (2) a clear-cut excitation maximum at 430 nm accompanied by a lower one at 320 nm. Hydrochloric acid vapor induces a hyposochromic shift of the 430 nm excitation maximum to 370-380 nm and a marked elevation of the 320 nm maximum. These results indicate fluorophores of DOPA and its derivatives; in this respect there are no marked differences between melanocytes, nevus cells and the cells of malignant melanoma.
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PMID:[Fluorescence histochemical and microfluorometrical investigations of pigmentary tumors of the skin (author's transl)]. 119 Aug 35

Lipoate acetyltransferase [acetyl-CoA: dihydrolipoate S-acetyl-transferase, EC 2.3.1.12], the core enzyme of the pyruvate dehydrogenase complex, has been highly purified by gel chromatography on Sepharose 6B and sucrose density gradient centrifugation in the presence of potassium iodide. The native enzyme has a sedimentation coefficient (S020,W) of 26.7S and a diffusion coefficient (D020,W) of 1.25 x 10(-7) cm2.-sec-1. The weight-average molecular weight was estimated to be 1.8 million from the sedimentation equilibrium data. The content of right-handed alpha helix in the enzyme molecule was estimated to be about 25% by optical rotatory dispersion and about 22% from the circular dichroism spectra. The enzyme was found to contain about 23 moles of protein-bound lipoic acid per mole of enzyme; some other properties are also reported. Lipoate acetyltransferase dissociated to yield a single subunit with a molecular weight of 74,000 as estimated by polyacrylamide gel electrophoresis in sodium dodecyl sulfate and by gel filtration on Bio-Gel in 6 M guanidine-HCl. The molecular weight was also estimated to be 74,000 from sedimentation equilibrium data in 6 M guanidine-HCl] containing 0.1 M 2-mercaptoethanol. Evidence is presented that 1 molecule of lipoate acetyltransferase apparently consists of 24 very similar subunits, each of which contains NH2-terminal alanine. Each subunit contains 1 molecule of covalently bound lipoic acid.
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PMID:Purification properties and subunit composition of pig heart lipoate acetyltransferase. 119 49

Purified ribulose-bisphosphate carboxylase (EC 4.1.1.39) was strongly and equally inhibited either by ADP or GDP and to a lesser extent by IDP. AMP or ATP exerted little effect on activity. Inhibition by the nucleotide diphosphates was competitive with respect to RuBP and non-competitive with respect to "CO2" and Mg2+, respectively. Treatment of the enzyme with urea or guanidine-HCl resulted in rapid loss of activity that was not restored by dialysis even in the presence of Mg2+ and cysteine. Sodium dodecyl sulfate electrophoresis of 8.0 M urea treated enzyme revealed the presence of a fast-moving (small) sub-unit with molecular weight 14150 and a slower moving (large) sub-unit with molecular weight 68000. Examination of native enzyme by sodium dodecyl sulfate electrophoresis gave sub-units of 13700 and 55500 respectively. The amino acid content standardized to phenylalanine was essentially similar to that from other sources. Arrhenius plots showed a "break" at 29 degrees C with an Ea of 12.34 kcal per mole for the steeper part of the curve and a deltaH of 11.43 kcal per mole while for the less steep region, the Ea was 1.04 kcal per mole and the deltaH 1.92 kcal per mole.
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PMID:Physical properties and metabolite regulation of ribulose bisphosphate carboxylase from Thiobacillus A2. 127 53

The effects of low-dose (10(-9) and 3 x 10(-9) mole/kg/min) infusions of dopexamine HCl, a new synthetic catecholamine with beta 2-adrenergic and DA1-dopaminergic agonostic actions, was tested in anesthetized dogs, with and without acute ligation of the left anterior descending coronary artery. The infusions caused diastolic arterial blood pressure to fall by 12 +/- 4 and 23 +/- 5 mmHg, respectively. Microsphere-estimated collateral blood flow to the ischemic myocardium did not change significantly during the drug infusions. The findings suggest that low doses of dopexamine HCl do not cause coronary "steal" from acutely ischemic myocardium.
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PMID:The effect of dopexamine HCl upon collateral perfusion of the acutely ischemic myocardium in anesthetized dogs. 198 May 79

The isocratic separation of dicarboxylic porphyrins (hematoporphyrin, hydroxyethylvinyl-deuteroporphyrin and protoporphyrin) and their isomers by normal-phase high-performance liquid chromatography is described. The stationary phase is unmodified silica and the mobile phase consists of acetone-ethyl acetate (1:1, v/v) mixtures containing water and inorganic acids. Retention (capacity factor, k') was found to decrease exponentially with the mole fraction of water (NH2O) and to increase linearly with the concentration of hydrochloric acid, following the relation k' = A [HCl] NH2O-4.85, where A is a constant characteristic of the porphyrin. The effects of the concentration and the nature of the acid used strongly suggest that retention involves a form of the porphyrin in which the inner nitrogens are protonated. The retention is thus partly determined by the basicity of the inner nitrogens, which depends on the electron-donating power of the porphyrin side-chains. Good resolution of the various components of hematoporphyrin derivative was obtained. In comparison with reversed-phase chromatography this method shows a different retention mechanism, appears to yield results of comparable reproducibility and provides complementary information. Possible retention mechanisms based on partition or adsorption equilibria are discussed.
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PMID:Normal-phase high-performance liquid chromatography of free acid dicarboxylic porphyrins and hematoporphyrin derivative on silica. 283 Feb 94

Reaction of Petunia hybrida 5-enol-pyruvylshikimate-3-phosphate synthase (EPSPS) with the arginine reagents phenylglyoxal (PGO) and p-hydroxyphenylglyoxal (HPGO) leads to inactivation of the enzyme. Inactivation with HPGO leads to modification of approximately 3 mol of arginine per mole of enzyme. The modification reaction follows pseudo-first-order kinetics with a t1/2 of 1 min at 5 mM p-hydroxyphenylglyoxal in 0.1 M triethanolamine HCl, pH 7.8. By titration of HPGO-modified enzyme with 5,5'-bis(dithio-2-nitrobenzoic acid), the possibility of cysteine modification by the arginine reagent was ruled out. While shikimate 3-phosphate (S3P) afforded partial protection to the enzyme against inactivation by HPGO, complete protection could be obtained by using a mixture of S3P and glyphosate. Under the latter conditions, only 1 mol arginine was modified per mole of enzyme. This pattern of reactivity suggests that two arginines may be involved in the binding of S3P and glyphosate to EPSP synthase. A third reactive arginine appears to be nonessential for EPSPS activity. Labeling of EPSP synthase with [14C]phenylglyoxal, peptic digestion, HPLC mapping, and amino acid sequencing indicate that Arg-28 and Arg-131 are two of the reactive arginines labeled with [14C]PGO.
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PMID:Arginine chemical modification of Petunia hybrida 5-enol-pyruvylshikimate-3-phosphate synthase. 317 27

We describe a fluorescence method for screening and quantifying urinary porphyrins. New and effective approaches are used to oxidize prophyrinogens, correct the baseline, and ensure that uroporphyrin (uro) and coproporphyrin (copro) are equally detected, mole for mole. No preliminary purification is required. A 45-microL aliquot of urine is oxidized with 3 mmol/L iodine in 3 mol/L HCl to convert porphyrinogens to porphyrins, and then decolorized with 5 mL of 0.45 mmol/L sodium thiosulfate. An excitation scan is done from 350 nm to 440 nm, monitoring emission at 650 nm. Total porphyrin content is determined at the isosbestic point for uro and copro, and the mole fractions of uro and copro are estimated from the wavelength of the signal maximum. There is no interference from protein, glucose, bilirubin, or hemoglobin in high concentration. The limit of detection is less than 30 nmol/L and linearity is maintained up to 3200 nmol/L. Recoveries and precision are excellent. This is a rapid, sensitive screen for porphyrinuria as well as an accurate and precise quantitative method. We compared the method with existing methods and discuss some shortcomings common to many of them.
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PMID:A rapid and accurate spectrofluorometric method for quantification and screening of urinary porphyrins. 334 8

A metallothionein isoform metallothionein-II was isolated from the livers of zinc acetate-treated rats. Metallothionein-II, which showed a single band on polyacrylamide gel electrophoresis, was subjected to two kinds of anti-ulcer screening systems. It was shown that intravenously administered metallothionein-II suppressed the formation of rat water-immersion stress- and HCl-ethanol-induced gastric ulcer significantly. The effect may partly be derived from the zinc contained in the metallothionein-II. However, the effect of metallothionein-II was much stronger than that of an equivalent mole of zinc. Apparently, metallothionein-II had an anti-ulcerogenic activity not based on the effect of intrinsic zinc.
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PMID:Suppression of gastric ulcer induced by stress and HCL-ethanol by intravenously administered metallothionein-II. 334 6

Transient ATP synthesized by preparations enriched with plasmatic membranes of particles from the human placenta in the presence of insulin (4 micrograms/ml) and epidermal growth factor (1 microgram/ml) within 1 min after the addition of hormones at 30 degrees C, was isolated by means of chromatography on Dowex 1 X 8. ATP was synthesized in a medium containing Tris-HCl buffer, pH 7.5, ADP, Mg2+, and Pi during NADH-dependent oxidation in the presence of cytochrome C and oxygen. The amount of ATP was 10(-9) mole/mg protein/min. Quantitative assessment of ATP in lyophilized product was carried out by means of fluorimetry (excitation wavelength--360 nm; emission wavelength--460 nm) of NADH formed during coupled enzymatic reactions involving hexokinase and glucose-6-phosphate dehydrogenase. A possible biological role of peptide growth factor-stimulated formation of transient ATP in plasmatic membranes is discussed.
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PMID:[ATP generation by the plasma membranes of human placental cells as affected by insulin and epidermal growth factor]. 354 74

The enthalpies of the guanidinium chloride (Gu.HCl) with sodium DNA salt in the solutions in B- and A-conformations in the mixtures of ethanol-water at 298.15 K and the enthalpies of solution of guanidinium chloride in the mixtures of ethanol-water at 298.15 K in a whole range of the compositions of mixed solvents were measured calorimetrically. It was established that in a field of B-A-transition of DNA the values of interaction enthalpies of Gu.HCl with DNA practically do not depend on the composition of the solvent. The concentrations of Na-ions in water-ethanol solutions of DNA containing Gu.HCl were determined by the potentiometric method. It was revealed that the interaction of the equimolar quantities of Gu.HCl and DNA leads to the complete replacement of Na-cations, which are naturally linked with DNA, into solution. From the results obtained the enthalpy of B-A-conformation transition DNA at 298.15 K was determined (-2.50 +/- 0.10 kJ/mole).
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PMID:[Determination of enthalpy of B-A transition of DNA in aqueous-ethanol solutions]. 368 75


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