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At least 109 records · Page 6Linked to original sources
PubMed1987

Phosphodiesterase from the venom of Crotalus ruber ruber.

Phosphodiesterase was isolated from the venom of Crotalus ruber ruber from the U.S.A. using the gel filtration on a Sephadex G-75 column, followed by anion or cation exchange chromatography. Phosphodiesterase was homogeneous as established by a single band on acrylamide gel electrophoresis and isoelectric focusing electrophoresis. Phosphodiesterase activity was inhibited by ethylenediamine tetraacetic acid (EDTA), o-phenanthroline, thioglycolic acid or p-chloromercuribenzoate (PCMB), but not by soybean trypsin inhibitor (SBTI) or benzamidine. The molecular weight of this enzyme was determined to be approx. 98,000 and the isoelectric point was found to be pH 10.5 by isoelectric focusing with carrier ampholyte. This enzyme contained 1.04 mol zinc per mol. The Michaelis constant (Km) of this enzyme for p-nitrophenyl thymidine-5'-phosphate and inhibition constant (Ki) for PCMB were found to be 8.3 X 10(-3) and 1.2 X 10(-2) M, respectively.

Amino Acids↗
PubMed1991

Densitometry for analysis of protein and peptide hydrolysates: application to luteinizing hormone releasing hormone.

Densitometric analysis has been performed on various standard protein and peptide solutions and on luteinizing hormone releasing hormone hydrolysate. After thin-layer chromatographic separation using two-dimensional separation on cellulose plates, the plates were mapped and each amino acid was assayed individually in order to obtain a specific integration profile of the hydrolysate. Densitometry proved to be a useful method for the screening of protein hydrolysates and is accurate enough for the assay of peptide hydrolysates. The hormone was hydrolysed with hydrochloric acid-trifluoroacetic acid (1:1, v/v) in the presence of thioglycolic acid. This limits the loss of tryptophan and does not interfere with the analysis. Results were sufficiently reliable, accurate and reproducible for routine analysis.

Chromatography, High Pressure Liquid↗
PubMed2004

Microanalysis of non-heme iron in animal tissues.

The method recommended by the Iron Panel of the International Committee for the Standardization in Haematology for measurement of serum iron was adapted for measurement of non-heme iron in animal tissues. The method developed was designed specifically to facilitate measurement of non-heme iron using as little as 10 mg of tissue, in a final reaction volume of 60 microl. In this assay, tissue homogenates are treated with hydrochloric acid and trichloroacetic acid and heated at 95 degrees C. Non-heme iron is released and protein is precipitated. Following centrifugation, iron in the supernatant is reacted with ferrozine in the presence of the reducing agent thioglycolic acid, and the complex is quantified by spectrophotometry. The method was validated by analysis of two Standard Reference Materials (bovine liver), comparing results of this assay against certified values and concentrations determined by flame atomic absorption spectrometry following acid digestion. Results using this method for analysis of non-heme iron in guinea pig tissues (liver, kidney and heart) compared favorably with those obtained using micro-scale adaptations of three published reference methods. The new method was more sensitive, required less time, and was less cumbersome than the three published methods to which it was compared.

Animals↗
PubMed2006

Synthesis and anticonvulsant activity of some potential thiazolidinonyl 2-oxo/thiobarbituric acids.

A series of 5-[(N-substituted benzylidenylimino)amino]-2-oxo/thiobarbituric acids (3a-3h) have been synthesized by the condensation of 5-hydrazino-2-oxo/thiobarbituric acids (2a-2b) with various aromatic aldehydes. Cycloaddition of thioglycolic acid to 3a-3h, yielded 5-[(2'-substituted phenyl-4'-oxothiazolidin-3'-yl)amino]-2-oxo/thiobarbituric acids (4a-4h). All these compounds were screened, in vivo, for their anticonvulsant activity and acute toxicity studies. Compounds 4f and 4g were found to be most potent compounds of this series and were compared with the reference drugs, phenytoin sodium, lamotrigine and sodium valproate. The structures of these compounds have been established by IR, 1H NMR and mass spectroscopic data.

Animals↗
PubMed1999

Application of a tetrazolium dye as an indicator of viability in anaerobic bacteria.

The use of the redox dye 5-cyano-2,3,-ditolyl tetrazolium chloride (CTC) for evaluating the metabolic activity of aerobic bacteria has gained wide application in recent years. In this study, we examined the utility of CTC in capturing the metabolic activity of anaerobic bacteria. In addition, the factors contributing to abiotic reduction of CTC were also examined. CTC was used in conjunction with the fluorochrome 5-(4,6-dichlorotriazinyl) aminofluorescein (DTAF), that targets bacterial cell wall proteins, to quantitate the active fraction of total bacterial numbers. Facultative anaerobic bacteria, including Escherichia coli grown fermentatively, and Pseudomonas chlorophis, P. fluorescens, P. stutzeri, and P. pseudoalcalegenes subsp. pseudoalcalegenes grown under nitrate-reducing conditions, actively reduced CTC during all phases of growth. Greater than 95% of these cells accumulated intracellular CTC-formazan crystals during the exponential phase. Obligate anaerobic bacteria, including Syntrophus aciditrophicus grown fermentatively, Geobacter sulfurreducens grown with fumarate as the electron acceptor, Desulfovibrio desulfuricans subsp. desulfuricans and D. halophilus grown under sulfate-reducing conditions, Methanobacterium formicicum grown on formate, H2 and CO2, and Methanobacterium thermoautotrophicum grown autotrophically on H2 and CO2 all reduced CTC to intracellular CTC-formazan crystals. The optimal CTC concentration for all organisms examined was 5 mM. Anaerobic CTC incubations were not required for quantification of anaerobically grown cells. CTC-formazan production by all cultures examined was proportional to biomass production, and CTC reduction was observed even in the absence of added nutrients. CTC was reduced by culture fluids containing ferric citrate as electron acceptor following growth of either G. metallireducens or G. sulfurreducens. Abiotic reduction of CTC was observed in the presence of ascorbic acid, cysteine hydrochloride, dithiothreitol, NADH, NADPH, Fe(II)Cl2, sodium thioglycolic acid and sodium sulfide. These results suggest that while CTC can be used to capture the metabolic activity of anaerobic bacteria, care must be taken to avoid abiotic reduction of CTC.

Bacteria, Anaerobic↗
PubMed1993

Determination of halfcystine in proteins as cysteine from reducing hydrolyzates.

The separation of cysteine from proline using a variant of the classical cation exchange system for amino acid analysis is described. From reducing hydrolyzates (6 M HCl/0.1% phenol/5% thioglycollic acid, 18 h, 110 degrees C) the halfcystine content of proteins can be accurately determined as cysteine. The system is useful for routine determination of the composition of proteins from a single type of hydrolyzate.

Chromatography, Ion Exchange↗
PubMed1984

[Structure of the hair in thallium poisoning].

The alterations in the hair roots discovered by Widy in 1956 were interpreted as accumulations of pigment which form as a consequence of a catalytic action of the poison. The goal of the present investigation was to clarify the structure of these inclusions. Hair from the heads of six victims who were involved in the poisoning of Würzburg medical students in January 1983 was available as investigation material. In the investigation in transmitted light and in polarized light, the black zones typical for thallium intoxication were found filling to varying extents the root and hair shaft near the root. Their intensity corresponded to the degree of severity of the intoxication. When examined under reflected light, the inclusions were shown up with a white color. They thus showed the same optical behavior as the air-filled medullary strand of normal hairs. This indicates that gaseous constituents are involved. This hypothesis could be confirmed by further investigations. After mechanical damage to the hair (pressing under high pressure), the gaseous inclusions disappeared and with them the "thallium strip." The same effect was attained by the chemical action of various acids, embedding agents, and dye solutions. This process was especially rapid after exposure to thioglycolic acid; the escape of the gas bubbles can be directly observed here. Scanning electron microscopic investigations on transverse sections of hair revealed a loosening of the spindle-shaped elements of the fiber layer as signs of structural disturbance. The gaseous constituents in thallium hair arise as the result of a trophic disorder in keratin formation. The structural alteration due to this leads to alopecia.

Adult↗
PubMed1976

Comparison of the physicochemical properties of fragment D derivatives of fibrinogen and fragment D-D of cross-linked fibrin.

The molecular weight of Fragment D derivatives obtained from plasmic digests of fibrinogen and cross-linked fibrin was determined by equilibrium sedimentation and compared with the summated molecular weight of their polypeptide chains observed after electrophoresis of reduced protein in sodium dodecyl sulfate polyacrylamide gels. The measured molecular weight of Fragment D (Stage 2) of fibrinogen is 103 500, which is compatible with a molecule containing only one each of the Aalpha (13 000), Bbeta (43 000) and gamma (39 000) chain remnants. Fragment D-D of cross-linked fibrin has a molecular weight of 189 000, compatible with a molecule containing one isopeptide-bound gamma-gamma chain (80 000) and two each of Bbeta (43 000) and Aalpha (13 000) chain remnants. The NH2-terminal amino acid residues of the Fragment D derivatives were measured quantitatively using a thioacetic-thioglycolic acid method, and molar quantities were calculated on the basis of the molecular weights determined by equilibrium sedimentation. Fragment D preparations obtained from Stage 2 and Stage 3 digests of fibrinogen have 3 mol of NH2-terminal amino acids per molecule, while Fragment D-D has seven. These data support the view that two Fragment D molecules, each of three polypeptide chains, are derived by plasmic degradation from each fibrinogen molecule, and that an isopeptide-bound, six chain Fragment D-D molecule is released from cross-linked fibrin by plasmin. Equlibrium sedimentation measurement of the molecular weights of Fragment X (Stage 1 and Stage 2) and Fragment Y are 265 000 and 148 000, respectively. These values are compatible with asymmetric cleavages of Fragment X to Fragments Y and D (Stage 2), and of Fragment Y to Fragments D (Stage 2) and E, and with a fibrinogen model in which the two halves are joined by disulfide bonds only in the amino-terminal regions.

Electrophoresis, Polyacrylamide Gel↗
PubMed1992

Determination of cysteine plus half-cystine in protein and peptide hydrolysates: use of dithiodiglycolic acid and phenylisothiocyanate derivatization.

Cysteine and half-cystine in proteins and peptides can be determined by acid hydrolysis in the presence of dithiodiglycolic acid, derivatization with phenyl isothiocyanate, and HPLC separation of the phenylthiocarbamyl amino acids. The determination requires no additional sample handling, oxidation, reduction, alkylation, or desalting. Samples containing cystine are treated in the same manner as those containing cysteine. Derivatization of cysteine or half-cystine by dithiodiglycolic acid has no effect on any other amino acids. Recovery of the PTC-cysteine derivative is greater than 90% over the linear range of 5 pmol to 1 nmol. Precision of the cysteine plus half-cystine determination is equivalent to that observed for all other amino acids. Structure work on the derivative indicates that it is a mixed disulfide containing cysteine and thioglycolic acid.

Amino Acid Sequence↗
PubMed1990

Intramolecular H-bonds and thioamide rotational isomerism in thiopeptides.

Mono- and dithionated N-acyl amino acid and dipeptide N'-methylamides were synthesized using Lawesson's reagent and S-thioacetyl thioglycolic acid. The conformation of the thionated models was characterized by IR, 13C, and 1H NMR spectroscopy, including NOE experiments. The formation of -C = S...H-N-C = X (X = O or S) intramolecular H-bonds of the type 2----2, 1----3 and 1----4 was evidenced by the characteristic shifts of the IR stretching frequencies of the NH group. Act-Pro-NHCH3(4) and Act-Prot-NHCH3(5) were found to be present as mixtures of rotational isomers about the CS-N bond. 13C chemical shifts of the gamma- and beta-carbons of the proline ring elucidated the conformation (Z or E) of the tertiary thioamide group. Our results suggest that the conformation of thiopeptides is determined by two factors: 1) the H-bond donating and accepting ability of the thioamide group and 2) the repulsion between the thiocarbonyl sulfur atom and the side chain groups of the neighbouring amino acid residues.

Dipeptides↗
PubMed1987

Amino acid analysis by high-performance liquid chromatography of a single stained protein band from a polyacrylamide gel.

A single stained band containing approximately 5 micrograms of protein was cut out of a polyacrylamide gel and subjected to hydrolysis together with the gel. The hydrolysate was subsequently analyzed for its amino acid content by high-performance liquid chromatography and postlabeling with o-phthalaldehyde. Bovine serum albumin, ribonuclease B, ovalbumin, pepsin, and chymotrypsinogen A were analyzed by this method, and their amino acid compositions were found to be in good agreement with the reported values. By this method, it is possible to quantitate 16 amino acids: Asx, Thr, Ser, Glx, Pro, Cys, Gly, Ala, Val, Ile, Leu, Tyr, Phe, His, Lys, and Arg. Thioglycolic acid is effective protection against the decomposition of Tyr, Cys, and Met; however, the recovery of Met is inconsistent. This method might be very helpful for the amino acid analysis of proteins of multicomponent systems, especially, those which can be resolved only by polyacrylamide gel electrophoresis.

Amino Acids↗
PubMed1968

Semi-automated method for the differential determination of plasma catecholamines.

A method is described for the estimation of adrenaline and noradrenaline in a 5 to 10 ml plasma sample.A batch technique of adsorption and elution from alumina is used and the final estimation is carried out using an automated fluorimetric technique based on the trihydroxyindole method. Fluorescence is stabilized first by thioglycollic acid to give noradrenaline concentrations only and then by ascorbic acid to give the total catecholamine concentration. The results of a number of catecholamine analyses are given.

Adsorption↗
PubMed1980

Attachment of Entamoeba histolytica to glass in a defined maintenance medium: specific requirement for cysteine and ascorbic acid.

Cysteine and ascorbic acid were previously shown to be required by Entamoeba histolytica trophozoites for attachment to glass, elongation, and ameboid movement as well as for short-term (12-24 h) survival in a balanced salt solution containing bovine serum albumin and a vitamin solution (Maintenance Medium 1). If the only function of cysteine and ascorbate was to decrease the redox potential, other reducing agents should be effective. However, the requirement for cysteine in the presence of ascorbic acid was highly specific. Equally effective were D- and L-cysteine; however, of many other compounds tested, only thioglycolic acid, ascorbic acid, or L-cystine (in decreasing order) were somewhat active. Under N2 atmosphere, cysteine and ascorbic acid were still required, although their concentrations could be halved. The ability to attach in the maintenance medium was irreversibly lost after only 5 min of cysteine-ascorbic acid deprivation; however, there was no decrease in viability when the amebae were transferred to growth medium within 30 min. Cysteine thiol groups in the medium were oxidized rapidly regardless of the concentration of ascorbic acid or the presence of amebae; however, ascorbic acid prolonged attachment of amebae.

Animals↗
PubMed1982

[Neutral and basic compounds present in gases produced by Clostridium sporogenes, Plectridium putrificum and Plectridium glycolicum cultured under vacuum in sodium thioglycolate glucose broth].

The study of gases produced by Clostridium sporogenes, Plectridium putrificum et P. glycolicum cultured under vacuum in sodium thioglycolate glucose broth makes possible the detection of compounds not described before for these Bacteria, particularly methyl-2 butanal and methyl-3 butanal for P. glycolicum and thiacyclopropane in these 3 Bacteria. Thiacyclopropane is the result of the cyclization of mercapto-2 ethanol produced by the reduction of thioglycolic acid.

Chemical Phenomena↗
PubMed1989

The effect of thioglycolate on intermediate filaments and membrane translocation in rat urothelium during the expansion-contraction cycle.

The functional role of cytokeratin intermediate filaments in the translocation of asymmetric membrane plaques between cytoplasm and surface of apical urothelial cells was investigated during contraction and expansion of rat urinary bladders. A stereological investigation of electron micrographs provided estimations of surface area, volume, and number of discoidal vesicles and infoldings per unit volume of urothelial apical cell cytoplasm. Contracted and distended bladders incubated in 0.01 M sodium bicarbonate were compared to identical preparations experimentally incubated in 5 mM thioglycolic acid. The latter reagent disrupts the intermediate filament network by reducing sulfhydryl bridges. Densities of discoidal vesicles in cells contracted after incubation in thioglycolate were similar to density estimations in cells expanded under control conditions. Similarly, densities of vesicles in cells expanded after exposure to thioglycolate were comparable in number to those in normally contracted cells. Thus, membrane translocation to and from the luminal surface was blocked by thioglycolate treatment. The lack of normal membrane transfer at the luminal surface induces apical cells exposed to experimental conditions to undergo extraordinary adjustments in response to external pressures of bladder contraction and distension. During contraction, the apical-intermediate cell interface unfolded while the luminal surface ballooned out into the lumen. In distended bladders, large intercellular spaces formed between apical cells along their lateral margins. The results support a model published earlier implicating the filament network as a critical mediator of membrane translocation.

Animals↗
PubMed1961

The use of specific antibody in electron microscopy. II. The visualization of mercury-labeled antibody in the electron microscope.

Glycerinated chicken muscle was stained with antimyosin antibody conjugated with mercury and fluorescein. The antibody was visualized in both the electron and the fluorescence microscope by using adjacent thin and thick sections. In order to make this possible, Araldite was used as the embedding medium. The mercury was reduced to metallic mercury in the electron beam and either migrated in the section or was sublimated in the vacuum. Therefore special techniques of carbon filming had to be used to prevent this. Some nonspecific staining occurred because of the binding of mercury to available sulfhydryl groups in the tissue. The available sulfhydryl groups were blocked by pretreating the tissue with iodoacetic acid and formaldehyde. The non-specific staining which occurred after this treatment was easily removed by brief washing with a buffered solution of thioglycolic acid.

Antibodies↗
PubMed1957

Chemical form of circulating antidiuretic hormone in rats.

Serum, taken from rats under ether anesthesia after injection of hypertonic saline, contained antidiuretic activity in a concentration equivalent to 1 to 3 millipressor units of pitressin per ml. The active material was retained by a collodion ultrafilter and, on electrophoretic analysis, moved with the beta globulins. Dialysis against 0.2 N acetic acid appeared to dissociate the complex. The antidiuretic factor was found in serum after stimuli known to cause release of pituitary antidiuretic hormone. Inactivation by thioglycolic acid and by proteolytic enzymes paralleled the inactivation of standard pitressin. Control experiments made it unlikely that serotonin, or any other substance released in the clotting of blood, could have contributed to the antidiuretic action. For these reasons it was concluded that the factor studied was native pituitary antidiuretic hormone circulating as a definite protein-peptide complex.

Animals↗