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PubMed1992

Electron spin echo envelope modulation spectroscopic study of iron-nitrogen interactions in myoglobin hydroxide and Fe(III) tetraphenylporphyrin models.

The electron-nuclear coupling in low-spin iron complexes including myoglobin hydroxide (MbOH) and two related model compounds, Fe(III) tetraphenylporphyrin(pyridine)(OR-) (R = H or CH3) and Fe(III) tetraphenylporphyrin(butylamine)(OR-) was investigated using electron spin echo envelope modulation (ESEEM) spectroscopy. The assignment of frequency components in ESEEM spectra was accomplished through the use of nitrogen isotopic substitution wherever necessary. For example, the proximal imidazole coupling in MbOH was investigated without interference from the contributions of porphyrin 14N nuclei after substitution of the heme in native Mb with 15N-labeled heme. Computer simulation of spectra using angle selected techniques enabled the assignment of parameters describing the hyperfine and quadrupole interactions for axially bound nitrogen of imidazole in MbOH, of axial pyridine and butylamine in the models, and for the porphyrin nitrogens of the heme in native MbOH. The isotropic component of axial nitrogen hyperfine interactions exhibits a trend from 5 to 4 MHz, with imidazole (MbOH) greater than pyridine greater than amine. The nuclear quadrupole interaction coupling constant e2Qq was near 2 MHz for all nitrogens in these complexes. The Qzz axis of the nuclear quadrupole interaction tensor for the proximal imidazole nitrogen in MbOH was found to be aligned near gz (gmax) in MbOH, suggesting that gz is near the heme normal. A crystal field analysis, that allows a calculation of rhombic and axial splittings for the d orbitals of the t2g set in a low-spin heme complex, based on the g tensor assignment gz greater than gy greater than gx, yielded results that are consistent with the poor pi-acceptor properties expected for the closed shell oxygen atom of the hydroxide ligand in MbOH. A discussion is presented of the unusual results reported in a linear electric field effect in EPR (LEFE) study of MbOH published previously [Mims, W. B., & Peisach, J. (1976) J. Chem. Phys. 64, 1074-1091].

Animals↗
PubMed2006

One-step advanced preparation of surface-functional peptide nanospheres by the polymerization of L-phenylalanine N-carboxyanhydride with dual initiators.

Surface-grafted peptide nanospheres consisting of hydrophobic poly(L-phenylalanine) with hydrophilic poly(ethylene glycol) (PEG) grafts were successfully prepared by the one-step polymerization of L-phenylalanine N-carboxyanhydride with the dual initiators of hydrophobic n-butylamine and hydrophilic NH2-monoterminated PEG (NH2-PEG). The monodispersed peptide nanospheres were stably self-assembled during polymerization in a mixture of water/dimethyl sulfoxide to create a colloidal solution, but only aggregated in water or organic solvents. When n-butylamine or NH2-PEG was used as a solitary initiator, the peptide nanospheres were not formed. The peptide nanospheres showed high dispersion-stability in water, and their diameter was approximately 300 nm. Furthermore, the peptide nanospheres were well-redispersed in water, retaining the same diameter and monodispersity even after lyophilization. Peptide nanospheres with the functional carboxylic acid on their graft layer were also successfully prepared by the one-step preparation method. This one-step preparation method of surface-grafted peptide nanospheres will be useful as an advanced technology to develop biodegradable functional nanospheres.

Butylamines↗
PubMed2005

From experiment to theory: molecular orbital parameters to interpret the skin sensitization potential of 5-chloro-2-methylisothiazol-3-one and 2-methylisothiazol-3-one.

5-Chloro-2-methylisothiazol-3-one (MCI) and 2-methylisothiazol-3-one (MI) are the major constituents of the commercial biocide Kathon CG. These two compounds have both been shown to exhibit skin sensitization potential: MCI is classified as an extreme sensitizer while MI is classified as a moderate sensitizer. The purpose of the present investigation was to provide further insights into the chemistry underlying their skin sensitizing properties. First, a molecular modeling (in silico) study was carried out of the initial reaction pathways of MI and MCI with nucleophiles representative of those involved in the skin sensitization process, and we compared the findings with the reported chemical and allergenic properties of these compounds. These reaction pathways were assessed using molecular orbital calculations. A novel parameter, the activation energy (AE) index, is proposed and is calculated from a knowledge of the energy changes in the frontier molecular orbitals as the electrophile is converted to an anionic intermediate. The AE indices correspond to the reactivity of MCI and MI with nucleophiles and also their skin sensitization potential. Second, the previously unexplained formation of final reaction products from MCI and butylamine is discussed and a reaction mechanism is proposed. A key finding of this analysis is that the reaction produces "positive chlorine" in the form of N-chloro- and/or N,N-dichloro-butylamine, which could contribute to the skin sensitizing properties of MCI.

Animals↗
PubMed2004

Imprinted polymers for chiral resolution of (+/-)-ephedrine: understanding the pre-polymerisation equilibrium and the action of different mobile phase modifiers.

A thorough study has been made of the ephedrine-methacrylic acid (MAA) system for molecular imprinting, involving NMR studies of the pre-polymerisation equilibria, modelling and HPLC enantioseparations with different mobile phases. When dimerisation of MAA is accounted for, NMR titrations demonstrate there is a very strong ('stoichiometric', K approximately 10000 M(-1)) interaction between ephedrine and a single MAA monomer. Polymers prepared with a 1:1 monomer:template ratio are capable of enantioseparation, indicating, in combination with the NMR results, that the 1:1 interaction probably involves the carboxylic acid acting as a chelating monomer, forming hydrogen bonds to both the template amine and hydroxyl moieties. Higher monomer:template ratios cause further changes in the NMR signals, suggesting at least one further MAA can interact with the amine group, with a weaker association constant (K approximately 80 M(-1)). Polymers prepared with a 4:1 monomer:template ratio are thus proposed to contain a mixture of 1-monomer binding sites and 2-monomer binding sites, the latter being of enhanced acidity. In HPLC, better results are obtained with the 4:1 polymer using acetic acid as a modifier, while better results are obtained for the 1:1 polymer using butylamine as a modifier. We propose a model whereby acetic acid exerts its effect by reducing binding to the 1-monomer sites, while butylamine works largely through blocking the most acidic, 2-monomer sites. For preparative chromatography we suggest the 1:1 polymer, with a larger population of weaker but more uniform binding sites, is most promising.

Acetic Acid↗
PubMed2001

New pathway of amine oxidation respiratory chain of Paracoccus denitrificans IFO 12442.

The physiological electron acceptor of quinohemoprotein amine dehydrogenase (QH-AmDH) from Paracoccus denitrificans IFO 12442 was identified by biochemical and electrochemical methods. Of three types of heme c-containing proteins purified together with QH-AmDH from the periplasm of n-butylamine-grown cells, only constitutive cytochrome c-550 was reduced by the addition of QH-AmDH and n-butylamine. Reconstitution of the respiratory chain revealed that cytochrome c-550 mediates the electron transfer from QH-AmDH to the terminal oxidase. This is a new pathway of the amine oxidation respiratory chain of P. denitrificans.

Amines↗
PubMed1990

Thermodynamic modeling of internal equilibria involved in the activation of trypsinogen.

The effect of activating dipeptides, sequentially homologous to the Ile16-Val17N-terminus of bovine beta-trypsin (beta-trypsin), on equilibria involved in the binding of strong ligands (i.e., n-butylamine, the bovine basic pancreatic trypsin inhibitor (Kunitz-type inhibitor; BPTI) and the porcine pancreatic secretory trypsin inhibitor (Kazal-type inhibitor, type I; PSTI)) to bovine trypsinogen (trypsinogen) was investigated at pH 5.51 (I = 0.1 M) and T = 21.0 +/- 0.5 degrees C; under the same experimental conditions, thermodynamics for the binding of strong ligands to beta-trypsin was also obtained. The equilibria involved in the binding of activating dipeptides and/or inhibitors to beta-trypsin and to its zymogen are described according to an induced-fit formalism, taking into account ligand-linked interaction(s) between different functional and structural domains of the (pro)enzyme possibly involved in the trypsinogen-to-beta-trypsin activation pathway. The analysis of data is focussed on parameters describing interactions between the so-called Ile-Val pocket (where the Ile16-Val17 N-terminus of beta-trypsin or activating dipeptides bind) and the primary and/or secondary recognition subsite(s) (where strong ligands associate) present in the (pro)enzyme. Such an analysis allows to dissect the contributions due to the primary recognition subsite, where small mono-functional ligands (e.g., n-butylamine) bind, from those of the secondary subsite(s), which are additional recognition clefts for macromolecular inhibitors (e.g., BPTI and PSTI).

Binding Sites↗
PubMed1980

New reaction of 4-chloro-7-nitrobenzofurazan with amines at high local concentrations. Primitive enzyme models.

The fluorogenic amine reagent 4-chloro-7-nitrobenzofurazan (CNBFz) reacts with amines to give one of two products, or a mixture, depending on the concentration of amine. At low concentrations (e.g. 5 X 10(-4) M) of unprotonated amine the normal replacement of the chlorine occurs, giving lambdamax approximately 470 nm. At high concentration of unprotonated amine (e.g. 0.5 M), a new product, lambdamax approximately 380 nm, is produced. At intermediate concentrations, both products are seen. These results were obtained with aqueous ammonia, methylamine and butylamine, and with butylamine in dry hexane. The 380 nm product also is obtained with high local concentrations of amines, such as with [lys]n at pH 8.5-10 and micellar dodecylamine at pH 9.5. These results are suggested to be analogous to those of very primitive proto-enzyme systems, by which clusters of small molecules can produce quantitative changes in "metabolism". Reaction of CNBFz with gelatin gave qualitative evidence for cross-linking.

4-Chloro-7-nitrobenzofurazan↗
PubMed2003

Polyamines as olfactory stimuli in the goldfish Carassius auratus.

Electrophysiological responses of goldfish olfactory receptor neurons (ORNs) and goldfish behavioral responses to polyamines were investigated in vivo. Electro-olfactogram (EOG) recordings indicated that polyamines (putrescine, cadaverine and spermine) are potent olfactory stimuli for goldfish with estimated electrophysiological thresholds of 10(-8)-10(-7) mol l(-1), similar to that for L-arginine, the most stimulatory amino acid. Although thresholds were similar, the magnitude of the EOG responses to intermediate (10(-5)-10(-4) mol l(-1)) and high (10(-3) mol l(-1)) concentrations of polyamines dwarfed the responses to amino acids and related single amine containing compounds (amylamine and butylamine). The EOG responses to 0.1 mmol l(-1) putrescine, cadaverine and spermine were, respectively, 4.2x, 4.3x and 10.3x the response of the standard, 0.1 mmol l(-1) L-arginine. Electrophysiological cross-adaptation experiments indicated that polyamine receptor sites are independent from those to L-amino acids (alanine, arginine, glutamate, lysine, methionine and ornithine), bile salts (sodium taurocholate and taurolithocholate), the single amine containing compounds (amylamine and butylamine) and ATP. Further, the cross-adaptation experiments revealed the existence of independent receptor sites for the different polyamines tested. Pharmacological experiments suggested that polyamine odorant transduction does not primarily involve the cyclic AMP and IP(3) second messenger pathways. Behavioral assays indicated that polyamines are attractants that elicit feeding behavior similar to that elicited by L-amino acids.

Amines↗
PubMed2001

Comparison of the omega-transaminases from different microorganisms and application to production of chiral amines.

Microorganisms that are capable of (S)-enantioselective transamination of chiral amines were isolated from soil samples by selective enrichment using (S)-alpha-methyl-benzylamine ((S)-alpha-MBA) as a sole nitrogen source. Among them, Klebsiella pneumoniae JS2F, Bacillus thuringiensis JS64, and Vibrio fluvialis JS17 showed good omega-transaminase (omega-TA) activities and the properties of the omega-TAs were investigated. The induction level of the enzyme was strongly dependent on the nitrogen source for the strains, except for V. fluvialis JS17. All the omega-TAs showed high enantioselectivity (E>50) toward (S)-alpha-MBA and broad amino donor specificities for arylic and aliphatic chiral amines. Besides pyruvate, aldehydes such as propionaldehyde and butyraldehyde showed good amino acceptor reactivities. All the omega-TAs showed substrate inhibition by (S)-alpha-MBA above 200 mm. Moreover, substrate inhibition by pyruvate above 10 mm was observed for omega-TA from V. fluvialis JS17. In the case of product inhibition, acetophenone showed much greater inhibitions than L-alanine for all omega-TAs. Comparison of the enzyme properties indicates that omega-transaminase from V. fluvialis JS17 is the best one for both kinetic resolution and asymmetric synthesis to produce enantiomerically pure chiral amines. Kinetic resolution of sec-butylamine (20 mM) was done under reduced pressure (150 Torr) to selectively remove an inhibitory product (2-butanone) using the enzyme from V. fluvialis JS17. Enantiomeric excess of (R)-sec-butylamine reached 94.7% after 12 h of reaction.

Amines↗
PubMed1985

Cross-link formation at the head-tail junction of mammalian spermatozoa during aging is dependent on sperm motility.

A high percentage of the heads of mouse, hamster, and rabbit spermatozoa were detached from their tails by vortexing a suspension of spermatozoa that had been incubated with dithiothreitol (DTT), a sulfhydryl reagent. Similar treatment of spermatozoa that had been aged under physiologic conditions for several hours and were still motile before reaction with DDT gave a much lower percentage of head detachment. This stabilization of the sperm head-tail junction developed only if spermatozoa were motile during aging. n-Butylamine also induced head detachment of mouse spermatozoa. Motile and immotile mouse spermatozoa became resistant to n-butylamine when aged in physiologic medium and buffer, respectively. However, stabilization developed much faster if spermatozoa were motile. Stabilization of the head-tail junction of motile spermatozoa to the reagents occurred over the time periods required for capacitation and the development of hyperactivated motility. Development of resistance to the two reagents may be biochemical events associated with capacitation.

Aging↗
PubMed2000

Mechanism of formation of elastin crosslinks.

We examined the formation of quaternary pyridinium crosslinks of elastin formed by condensation of lysine and allysine residues using the model compounds propanal (allysine) and n-butylamine (lysine) under quasi-physiological conditions. The resulting pyridinium compounds were characterized and the structure compared with the known pyridinium crosslinks. Three pyridinium compounds were identified and the structures were identical with the skeleton of the crosslinking amino acids, desmosine (DES), isodesmosine (IDE), and pentasine. We concluded that a non-enzymatic pathway is available for the spontaneous generation of pyridinium crosslinks. To elucidate the intermediates and the mechanism of the formation of DES and IDE, we synthesized model intermediates from propanal and n-butylamine, and they were allowed to react in three kinds of solvents. Then, the products were analyzed by an ion-pair reverse-phase HPLC. The results of this model system indicated that DES and IDE can be formed by condensation of dehydromerodesmosine with dehydrolysinonorleucine and by condensation of allysine with dehydrolysinonorleucine, respectively. We also describe the mechanism of DES and IDE crosslinking.

2-Aminoadipic Acid↗
PubMed2004

[Preparation and FTIR properties of amino compounds modified glutaraldehyde crosslinked chitosan resin activated with cyanuric chloride].

The preparation and IR properties of 1-butylamine, dimethylamine, trimethylamine, triethylamine, benzylamine, 4-methylaniline and 4-aminobenzenesulfonic acid modified glutaraldehyde crosslinked chitosan activated with cyanuric chloride were studied. The absorption of nu(O-H) and nu(N-H) at 3430-3440 cm(-1), nu(C-O-C) at 1155 cm(-1), nu(C-OH) at 1030 cm(-1) and nu(C-O) of beta-D-glucose at 899 cm(-1) were not shifted obviously. The absorption of delta(C-H) at 1400-1384 cm(-1) and nu(C-OH) at 1095 cm(-1) varied markedly. The nu(C=N) absorption of crosslinked chitosan was at 1640-1650 cm(-1). The skeleton vibration absorption of 1,3,5-triazine ring was at 803-812 cm(-1) and 1584-1590 cm(-1). With different deacetylation or substitution, the amide I, II, III absorption at 1650, 1600 and 1310 cm(-1) varied obviously. When modified with 1-butylamine, dimethylamine, benzylamine, 4-methylaniline and 4-aminobenzenesulfonic acid, strong absorption of delta(NH3+) appeared at 1517-1530 cm(-1), which was weakened or disappeared when modified with trimethylamine or triethylamine, but a series of new absorption of nu(C-N) appeared at 1400-1500 cm(-1).

Butylamines↗
PubMed1986

Reaction pathway of bovine aortic lysyl oxidase.

The catalysis of amine oxidation by lysyl oxidase has been probed to assess for the likely order of substrate binding and product release and to discriminate between mechanistic alternatives previously proposed for other copper-dependent amine oxidases using molecular oxygen as a substrate. Lineweaver-Burk plots revealed a pattern of parallel lines when the oxidation of n-butylamine was followed at different fixed concentrations of oxygen consistent with a "ping-pong" kinetic mechanism in which the aldehyde is produced and released before the binding of oxygen, the second substrate. Initial burst experiments revealed the ability of lysyl oxidase to form and release n-butyraldehyde in amounts stoichiometric with functional active site content in the absence of oxygen, consistent with the ping-pong kinetics obtained. Reciprocal plots of n-butylamine oxidation in the presence of fixed concentrations of the reaction products were consistent with a Uni Uni Uni Bi ping-pong kinetic mechanism with the aldehyde being the first, H2O2 the second, and ammonia the last departing product. Moreover, spectral studies of the oxidation of p-hydroxybenzylamine by lysyl oxidase indicated that the enzyme does not process the amine substrate to a noncovalently bound p-hydroxybenzaldimine intermediate subsequently to be hydrolyzed to p-hydroxybenzaldehyde. The kinetic mechanism of lysyl oxidase thus appears to be similar to those described for diamine oxidase and pig plasma monoamine oxidase.

Aldehydes↗
PubMedDate not supplied

Effect of aliphatic monoamines on motor activity of mice: no direct interaction with dopaminergic D2 receptor.

The effect of butylamine, pentylamine and hexylamine on spontaneous locomotor activity of mice was evaluated in the presence or absence of drugs affecting monoaminergic neurons. Pentylamine and hexylamine produced similar effects (stimulation after low, inhibition after high doses), while butylamine action was weak. Depression of locomotor activity produced by combined treatment with alpha-methyl-tyrosine, reserpine and dopa was counteracted by pentylamine and hexylamine; they did not produce such an effect in the absence of dopa. The amines did not displace 3H-spiperone specifically bound to striatal membranes.

Amines↗
PubMed1981

Estimation, prevention, and quality control of carbon dioxide loss during aerobic sample processing.

We find that 2 to 6 mmol of carbon dioxide per liter (mean: 4.1 mmol/L) is lost during routine laboratory processing of patients' serum samples after centrifugation. Additional CO2 may be lost if evacuated blood-collection tubes are not filled completely during phlebotomy. More than 2 mmol of CO2 per liter is lost from samples stored in tightly stoppered tubes for 120 min if the tubes are less than half full. In extreme cases, 8 mmol of CO2 per liter may be lost from samples exposed to room air in open cups of automated micro-sample instruments. Clinically significant CO2 loss (greater than 2 mmol/L) before analysis is not detected by many laboratories because the generally accepted quality-control programs monitor only the very last step of the analytical process. A valid CO2 quality-control program should include samples with high as well as the generally used low pCO2 values. Alkalinization of serum and plasma samples with tert-butylamine prevents CO2 loss. Optimum tert-butylamine concentration, pH, and pCO2 were about 14 to 16 mmol/L, 9.0 to 9.3, and 0.4 to 1.5 mmHg (about 50 to 200 Pa).

Autoanalysis↗
PubMed2000

Reactivity of dioxoruthenium(VI) porphyrins toward amines. Synthesis and characterization of bis(arylamine)ruthenium(II), bis(arylamido)- and bis(diphenylamido)ruthenium(IV), and oxo(tert-butylimido)ruthenium(VI) porphyrins.

Reactions of dioxoruthenium(VI) porphyrins, [Ru(VI)O2(Por)], with p-chloroaniline, trimethylamine, tert-butylamine, p-nitroaniline, and diphenylamine afforded bis(amine)ruthenium(II) porphyrins, [Ru(II)(Por)(L)2] (L-p-ClC6H4NH2, Me3N, Por=TTP, 4-Cl-TPP; L=tBuNH2, Por = TPP, 3,4,5-MeO-TPP, TTP, 4-Cl-TPP, 3,5-Cl-TPP) and bis(amido)ruthenium(IV) porphyrins, [Ru(IV)(Por)(X)2] (X=p-NO2C6H4NH, Por=TTP, 4-Cl-TPP; X = Ph2N, Por = 3,4,5-MeO-TPP, 3,5-Cl-TPP), respectively. Oxidative deprotonation of [Ru(II)(Por)(NH2-p-C6H4Cl)2] in chloroform by air generated bis(arylamido)ruthenium(IV) porphyrins, [RuIV(Por)(NH-p-C6H4Cl)2] (Por=TTP. 4-Cl-TPP). Oxidation of [RuII(Por)-(NH2tBu)2] by bromine in dichloromethane in the presence of tert-butylamine and traces of water produced oxo(imido)ruthenium(VI) porphyrins, [RuVI-O(Por)(NtBu)] (Por=TPP, 3,4,5-MeO-TPP, TTP, 4-Cl-TPP, 3,5-Cl-TPP). These new classes of ruthenium complexes were characterized by 1H NMR, IR, and UV/visible spectroscopy, mass spectrometry, and elemental analysis. The structure of [Ru(IV)(TTP)(NH-p-C6H4Cl)2 . CH2Cl2 was determined by X-ray crystallography. The Ru-N bond length and the Ru-N-C angle of the Ru-NHAr moiety are 1.956(7) A and 135.8(6) degrees, respectively.

Amines↗
PubMedDate not supplied

Determination of low molecular weight aliphatic primary amines in urine as their benzenesulphonyl derivatives by gas chromatography with flame photometric detection.

A selective and sensitive method for the determination of low molecular weight aliphatic primary amines in urine is described. These amines were converted into their benzenesulphonyl derivatives by a modified Hinsberg procedure, and measured by gas chromatography with flame photometric detection (FPD-GC) using a DB-1 capillary column. The derivatives were very stable and provided excellent FPD responses. By FPD-GC, linear calibration curves were obtained in the range 10-200 ng of methylamine, ethylamine, n-propylamine, isobutylamine and n-butylamine using tert-butylamine as an internal standard, and the detection limits of these amines were ca. 6-25 pg as the injection amount. Benzenesulphonamide derived from ammonia was converted into its N-dimethylaminomethylene derivative which has a longer retention time, and separated from benzenesulphonyl derivatives of low molecular weight primary amines on the chromatogram. The recoveries of aliphatic primary amines added to urine samples were 91-107% and the relative standard deviations were 0.2-4.5%. Analytical results of aliphatic primary amine contents in urine samples of normal subjects are presented.

Adult↗
PubMed2001

R2PI Study of intermolecular hydrogen bond in solvent-free chiral complexes.

One- and two-color, mass selected R2PI spectra of the S(1)<--S(0) transitions in the bare (+)-(R)-1-phenyl-1-ethanol (E(R)) and its complexes with different solvent molecules (solv) (-)-(R)-2-butanol (B(R)) or (+)-(S)-2-butanol (B(S)) and (-)-(R)-2-butylamine (A(R)) or (+)-(S)-2-butylamine (A(S)), have been recorded after a supersonic molecular beam expansion. The one-color R2PI excitation spectra of the diastereomeric complexes are characterized by significant shifts of their band origin relative to that of bare E(R). The extent and the direction of these spectral shifts are found to depend on the structure and the configuration of solv and are attributed to different short-range interactions in the ground and excited states of the complexes. In analogy with other diastereomeric complexes, the phenomenological binding energy of the homochiral cluster is found to be greater than that of the heterochiral one.

Journal Article↗