Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “AMIDES”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,117 records · Page 62Linked to original sources
PubMed1989

Anticoagulant and antithrombotic properties of synthetic sulfated bis-lactobionic acid amides.

Sulfated bis-lactobionic acid amides, a new class of polyanions with heparin-like properties, were synthesized and their antithrombotic and anticoagulant activities were determined. Compared to heparin and Fragmin, a low molecular weight heparin, the substances exhibited moderate to low anticoagulant activities in aPTT, thrombin clotting time and Heptest assays. In amidolytic assays no anti-IIa activity and only exceedingly low anti-Xa activity was observed. The antithrombotic activity of the bis-lactobionic acid amides was determined using two thrombosis models. In rabbit and rat models thrombi were induced by a combination of endothelial damage and reduction of blood flow or only by endothelial damage. At least one of the bis-lactobionic acid amides (LW 10082) exhibited a considerable antithrombotic activity which was similar to low molecular weight heparin.

Animals↗
PubMed1985

Chloroacryloyl amides and alpha-methylenelactones from naltrexone, oxymorphone and fentanyl.

A series of chloroacryloyl amides and alpha-methylenelactones were prepared from naltrexone and oxymorphone and some chloroacryloyl amides from fentanyl were prepared as potential Michael acceptors and irreversible ligands. The relative rates of Michael additions of p-methoxybenzenethiol to the double bonds were measured in an NMR spectrometer. The IC50's in rat brain homogenates and the irreversible binding to rat brain membranes were determined. In the methylene-lactone series, it was found that both the alpha and beta isomers derived from naltrexone and oxymorphone were excellent Michael acceptors, but only the beta isomers were more active in the opioid binding assays. The beta isomer derived from naltrexone was an irreversible ligand whereas the oxymorphone analogue was active only in the presence of 100 mM NaCl. In the chloroacryloyl series, only the alpha-chloroacryloyl amide derived from beta naltrexamine proved to be an irreversible binding ligand in the absence of NaCl. It was an excellent Michael acceptor. Under the conditions of our experiments, beta-FNA was a poor Michael acceptor and did not behave as an irreversible ligand in rat membranes.

Acrylates↗
PubMed1985

A rapid, sensitive assay for glycine-directed amidating enzymes.

Current assays for glycine-directed, peptide-amidating enzymes have several shortcomings. In this report, we describe a rapid, sensitive microassay for amidating activity which overcomes these disadvantages. Tissue homogenates are incubated in the presence of D-Tyr-Val-Gly-OH and the product, D-Tyr-Val-NH2, is measured by radioimmunoassay using an antiserum with an affinity for the product, D-Tyr-Val-NH2 (Kaff 2 X 10(8) L/M), 4 orders of magnitude higher than for the substrate, D-Tyr-Val-Gly-OH (Kaff 4 X 10(4) L/M), and 3 orders of magnitude higher than for the deamidated product D-Tyr-Val-OH (Kaff 8 X 10(5) L/M). Addition of N-ethylmaleimide (0.5 mM) to the enzyme incubates prevents the degradation of D-Tyr-Val-NH2 and permits the measurement of enzymatic activity in crude homogenates. This assay is sensitive enough to permit the measurement of amidating activity in crude rat brain homogenates containing as little as 4-8 micrograms protein.

Animals↗
PubMed1985

Metorphamide, a C-terminally amidated opioid peptide, in human adrenal and human phaeochromocytoma.

There appears to be only one possible site for the production of an amidated peptide in the human proenkephalin sequence; this will give rise to the peptide named metorphamide. Since amidation of peptides is commonly an activation step in the synthesis of regulatory peptides, we have examined the levels and form of immunoreactivity to metorphamide in human post-mortem adrenal and phaeochromocytoma extracts. In three out of four post-mortem adrenal extracts, and in each of the two phaeochromocytoma extracts examined, there was 3-4 times more immunoreactivity to the carboxy-terminus of pro-enkephalin, Met-enkephalin(Arg6,Phe7), than to metorphamide. The metorphamide immunoreactivity was shown in each extract to measure only the amidated octapeptide according to gel exclusion and reverse-phase chromatography data. The implications for processing of proenkephalin in human adrenal are indicated.

Adrenal Gland Neoplasms↗
PubMed1994

Characterization of peptidylglycine alpha-amidating monooxygenase in bovine hypothalamus.

In many peptide hormones and neuropeptides, the carboxyl-terminal alpha-amide structure is essential in eliciting their biological activity. In the present study, an enzymatic activity capable of converting 4-dimethylaminoazobenzene-4'-sulfonyl-Gly-L-Phe-Gly(Dabsyl-Gly-Phe -Gly) to 4-dimethylaminoazo-benzene-4'-sulfonyl-Gly-L-Phe-NH2(Dabsyl- Gly-Phe-NH2) was investigated in bovine hypothalamus. The concentrations of copper ion and ascorbic acid required for maximal enzyme activity were 16 microM and 2 mM, respectively. Amidating activity showed a pH profile with two pH optima at acidic pH (around 6.0) and neutral pH (around 7.5). Kinetic studies with the enzyme obtained from bovine hypothalamus demonstrated two distinct Km and Vmax values. The first Km and Vmax values were 142.9 microM and 22.2 pmol/microgram/h and the second Km and Vmax values were 22.7 microM and 4.44 pmol/microgram/h, respectively. Two molecular forms of amidating activity were identified by size-exclusion chromatography and the molecular weight of the two enzymes were estimated to be 49 kDa and 69 kDa.

Amino Acid Sequence↗
PubMed1995

Oral immunoadjuvant activity of lipophilic derivatives of N-acetylglucosaminyl-beta(1-->4)-N-acetylmuramyl-L-alanyl-D-isoglutamin yl-(L)- 2,6-meso-diaminopimeric acid-(D)-amide.

Twenty-four kinds of the acylated, amidated or esterified derivatives of N-acetylglucosaminyl (GlcNAc)-beta(1-->4)-N-acetylmuramyl (MurNAc)-L-alanyl (Ala)-D-isoglutaminyl (isoGln)-(L)-meso-2,6-diaminopimeric acid (A2pm)-(D)-amide (GMP3-A) which were prepared by chemical modifications of an enzymatic hydrolysate of Lactobacillus plantarum cell-wall peptidoglycans were examined for oral adjuvant activity by gastric intubation with bovine serum albumin (BSA) in liposomes into BALB/c mice. The gastric intubation of GlcNAc-beta(1-->4)-MurNAc-L-Ala-D-isoGln-(L)- stearoyl-(D)-meso-A2pm-(D)-amide-(L)-O-octyl, -nonyl and -dodecyl esters exhibited the most marked oral adjuvant activity in terms of enhanced production of serum anti-BSA IgG antibody. Some derivatives showed a less marked adjuvanticity and others were totally inactive. Thus the oral adjuvanticity of test lipophilic derivatives of GMP3-A in liposomes was dependent upon their chemical structure.

Adjuvants, Immunologic↗
PubMed1990

Interaction of ATP with acetyl-CoA carboxylase from rat liver. The role of the polyphosphate chain. Affinity labelling with alkylating amides of ATP and ADP.

The interaction of a number of ATP analogs with a modified triphosphate moiety as well as 2-chloro-ethyl-amino derivatives of nucleotides, 4(N-2-chloroethyl-N-methylamino)-benzyl-gamma-amide of ATP and the corresponding ADP beta-amide with acetyl-CoA carboxylase (EC 6.4.1.2.) from rat liver has been studied. Halophosphonate derivatives of ATP have been synthesized from bromomethylene diphosphonic acid and found to be reversible inhibitors of the enzyme. ATP and ADP alkylating amides have proved to form a reversible complex with the ATP-binding site and to modify a group in the acetyl-CoA-binding site. The bicarbonate ion accelerates the process of inactivation. The estimate of the distance between the ATP-binding site and the acetyl-CoA-binding site ranges within 0.8-1.2 nm.

Acetyl-CoA Carboxylase↗
PubMed1985

[13N]Ammonia and L-[amide-13N]glutamine metabolism in glutaminase-sensitive and glutaminase-resistant murine tumors.

The short-term metabolic fate of labeled nitrogen derived from [13N]ammonia or from L-[amide-13N]glutamine was determined in murine tumors known to be resistant (Ridgeway Osteogenic Sarcoma (ROS] or sensitive (Sarcoma-180 (S-180)) to glutaminase therapy. At 5 min after intraperitoneal injection of [13N]ammonia or of L-[amide-13N]glutamine, only about 0.7% of the label recovered in both tumors was in protein and nucleic acid. After [13N]ammonia administration, most of the label (over 80%) was in a metabolized form; a large portion of this metabolized label (50-57%) was in the urea fraction with a smaller amount in glutamine (37-42%). The major short-term fate of label derived from L-[amide-13N]glutamine was incorporation into components of the urea cycle with smaller amounts in the acidic metabolites and in acidic amino acids. No labeled urea was found during in vitro studies in which S-180 tumor slices were incubated with [13N]ammonia, suggesting that the [13N]urea formed in the tumor in the in vivo experiments was not due to de novo synthesis through carbamyl phosphate in the tumor. Both tumors exhibited very low glutamine synthetase activity. Following glutaminase treatment, glutamine synthetase and gamma-glutamyltransferase activities, while remaining low, increased in the resistant tumor but not in the sensitive tumor; this increase may be related to the insensitivity of the ROS tumor toward glutaminase treatment.

Amino Acids↗
PubMed1982

Nitrogen metabolism in goldfish, Carassius auratus (L.) activities of amidases and amide synthetases in goldfish tissues.

1. Activities of asparagine synthetase, asparaginase, glutamine synthetase and glutaminase have been determined in red muscle, white muscle, brain, kidney, liver and gills of goldfish. 2. Muscle and brain show a capacity for net amide synthesis, while liver and gills are capable of both amide synthesis and degradation. 3. These results are consistent with the hypothesis that amide synthesis and degradation functions as a mechanism controlling tissue ammonia levels and ammonia excretion rates.

Animals↗
PubMed1987

Effect of insulin on excretion and retention of infused glutamine amide-N in chickens (Gallus domesticus).

1. The purpose of this study was to examine the effects of insulin on urinary excretion and retention of the intravenously infused glutamine amide-15N in chickens. 2. Insulin pretreatment reduced urinary total 15N excretion (P less than 0.05) and enhanced 15N retention in chicken body (P less than 0.05), but it did not affect non protein-15N retained in the liver and blood. 3. Insulin decreased the incorporation of the infused glutamine amide-15N into urinary uric acid as well as the excretion of other N-derived urinary uric acid (P less than 0.05), which resulted in a significant decrease in total urinary uric acid (P less than 0.05). 4. There was no effect of insulin on urinary appearance of the infused glutamine amide-15N in the form of ammonia.

Ammonia↗
PubMed1995

Preparation, physico-chemical characterization, and relaxometry studies of various gadolinium(III)-DTPA-bis(amide) derivatives as potential magnetic resonance contrast agents.

Macroscopic protonation constants were measured for a series of DTPA mono- and bis-amide ligands using potentiometric titrations. Proton NMR pH titrations yielded protonation populations of the various nitrogen and oxygen basic sites of the ligands for the different protonation stages. Amide formation decreased the basicity of the backbone nitrogens of the ligands and the thermodynamic stability of the corresponding Gd3+ chelates. Nuclear magnetic relaxation dispersion (NMRD) profiles and ESR linewidths were measured for the Gd3+ chelates. Some of these exhibited an elevated high field relaxivity relative to Gd(DTPA)2-, in response to their high molecular weight. As opposed to Gd(DTPA)2-, at 5 degrees C the chemical exchange process of the single inner-sphere water molecule of the bis-amide complexes becomes so slow that it governs the paramagnetic relaxation process, causing the observed NMRD profiles to be close to those expected for the outer-sphere contribution. The chelates containing long alkyl side chains, such as Gd(DTPA-HPA2), showed increased relaxivity values in the presence of human serum albumin (HSA), indicative of noncovalent interaction with the protein. These chelates could be useful as nonionic hepatobiliary contrast agents.

Contrast Media↗
PubMed1995

Thermospray liquid chromatography/mass spectrometry study of diastereomeric isoindole derivatives of amino acids and amino acid amides.

A thermospray liquid chromatography/mass spectrometry (TSP-LC/MS) method is described for determination of the enantiomeric excess of alpha-amino acids and alpha-amino acid amides as their o-phthalaldehyde/N-acetyl-L-cysteine (OPA/NAC) derivatives. The source temperature is an important factor in optimizing the sensitivity of the TSP-LC/MS analysis, whereas the repeller voltage is of minor importance. On-column mass spectra were acquired for the OPA/NAC derivatives of several alpha-amino acids and alpha-amino acid amides. For the main fragment ions, mass spectra fragmentation pathways are proposed. The applicability of the method is demonstrated by means of the enantiomeric excess determination of valine in a sample from an enzymatic hydrolysis experiment. Using single ion monitoring, the detection limit of D-valine in the presence of excess L-valine is 10 pmol. The present TSP-LC/MS method is useful for validating the results obtained from LC/UV or LC/fluorescence methods for the enantiomeric excess determination of alpha-amino acids and alpha-amino acid amides.

Acetylcysteine↗
PubMed1995

GIP and GLP-1(7-36)amide secretion in response to intraduodenal infusions of nutrients in pigs.

Investigation of nutrient stimulation of two gut hormones GIP (glucose dependent insulotropic polypeptide) and GLP-1(7-36)amide (the active truncated form of glucagon-like peptide-1) is made difficult by the differential control of gastric emptying. Direct nutrient infusion into the duodenum was therefore carried out on three female pigs. The infusates consisted of saline (0.85 g or 1.7 g/100 ml); glucose (20 g or 40 g/100 ml); fat (30 g or 60 g/500 ml) and glucose/fat (20 g and 30 g or 40 g and 60 g per 1000 ml). Plasma glucose levels were elevated as expected by glucose or glucose/fat infusions, and they were not affected by the presence of fat in the infusate. Insulin secretion was stimulated in the presence of glucose or glucose/fat. Plasma triacylglycerol was elevated following fat and glucose/fat infusions. The greatest stimulus for GIP secretion was glucose/fat (P < 0.05); fat alone was a poor stimulus for GIP secretion, but glucose was a potent stimulus. GLP-1(7-36)amide was moderately stimulated by glucose and markedly stimulated by fat and glucose/fat infusions (P < 0.05). We conclude that, in pigs, dual nutrient infusion of glucose/fat is a strong stimulus for both GIP and GLP-1(7-36)amide secretion. The hormones therefore have the potential to play an important physiological role, both in the stimulation of insulin secretion and in adipose tissue metabolism in pigs.

Analysis of Variance↗
PubMed1991

Peptide amidation.

Many hormones, neurotransmitters and growth factors are peptides that carry an amide group at their carboxyl terminus which is essential for their biological activity. The amide is formed by hydroxylation of an additional glycine residue present in the biosynthetic precursor and the hydroxyglycine derivative dissociates to form the peptide amide and glyoxylic acid. Recent discoveries have shown that two enzymes are involved that act sequentially.

Amidine-Lyases↗
PubMed2004

Presumptive FMRF-amide-like immunoreactive retinopetal fibres in Crocodylus niloticus.

A small contingent of 30-50 of centrifugal visual fibres, showing FMRF-amide-like immunoreactivity, has been identified in C. niloticus; these fibres extend from the chiasmatic region into the retina. They do not take the marginal optic tract, but pass medially to the chiasmatic fascicles, from the preoptic region. The cells of origin of these fibres have not been identified. However, none of the retinopetal neurons of the brainstem [M. Medina, J. Reperant, R. Ward, D. Miceli, Centrifugal visual system of Crocodylus niloticus : a hodological, histochemical and immunocytochemical study, J. Comp. Neurol. 468 (2004) 65-85], labelled by retrograde transport of rhodamine beta-isothiocyanate after intraocular injection of this tracer, show FMRF-amide-like immunoreactivity; neither are any of the FMRF-amide-like immunopositive neurons in the crocodile brain, particularly those of the complex involving the terminal nerve and the septo-preoptic region, labelled by rhodamine after its intraocular injection.

Alligators and Crocodiles↗
PubMed2005

Ubiquitin and ubiquitin-derived peptides as substrates for peptidylglycine alpha-amidating monooxygenase.

Ubiquitin (Ub) and the ubiquitin-like proteins (UBLs) mediate an array of cellular functions. These proteins contain a C-terminal glycine residue that is key to their function. Oxidative conversion of C-terminal glycine-extended prohormones to the corresponding alpha-amidated peptide is one step in the biosynthesis of bioactive peptide hormones. The enzyme catalyzing this reaction is peptidylglycine alpha-amidating monooxygenase (PAM). We report herein that Ub is a PAM substrate with a (V/K)(amidation) that is similar to other known peptide substrates. This work is significant because PAM and the UBLs co-localize to the hypothalamus and the adrenal medulla and are both over-expressed in glioblastomas.

Amino Acid Sequence↗
PubMed2006

Observation of pronounced b*,y cleavages in the electron capture dissociation mass spectrometry of polyamidoamine (PAMAM) dendrimer ions with amide functionalities.

We report the electron capture dissociation (ECD) mass spectrometry of the third generation polyamidoamine (PAMAM) dendrimer that contains amide functionalities. The dendrimer was chosen because it offers a unique opportunity to understand the ECD behavior of the amide functionality in a framework other than peptides/proteins. In this study, PAMAM ECD was found to exhibit a fragmentation pattern strikingly different from that of ordinary peptide/protein ECD. Specifically, ECD of multiply protonated PAMAM ions gave rise to significant b(*),y cleavages as well as S,E dissociations but, unexpectedly, only minor c,z(*) fragmentations are observed. In an effort to account for the unexpectedly different fragmentation pattern, a comparative ECD experiment on the poly(propylene imine) dendrimer in which the amide bond moiety is not available and density functional theory calculations (B3LYP/6-311 + G(d)) investigations on the model system of a charge-solvated single-repeat unit were carried out. On the basis of these results, we discuss here possible implications of intramolecular charge-solvation, energy barriers in dissociation reactions, and macromolecular properties of the dendritic molecule for understanding the reaction pathway of PAMAM ECD.

Journal Article↗
PubMed2005

Volumetric behavior of a bolaamphiphile in different amides-water and ethylene glycol-water mixtures.

The effect of binary aqueous mixtures of ethylene glycol (EG), formamide (FA), N-methylformamide (NMF), dimethylformamide (DMF), and their pure phase on the apparent molar volume phi(V) of the bolaamphiphile decamethonium bromide (C10Me6) has been investigated at 298.15 K. The behavior of standard molar volumes V2(0) and transfer volumes Delta(t)phi(V) of C10Me6 from water to solvent/water (S/W) binary mixtures, shows different minima and maxima depending on the composition of the solvent. This behavior is influenced by the nature of the cosolvent and on the type of the solute and more or less corresponds to volumetric changes in the S/W mixture. The investigation of the transfer volumes in different fixed concentrations reveals an inversion of Delta(t)phi(V) values between the compositions, which suggests a differentiation of the effects of different volume contributions on the partial molar volume of ions. The correlation of Delta(t)phi(V) with the dielectric constant of the aqueous amide mixtures shows that the behavior of Delta(t)phi(V) vs x(amide) reflects the changes of epsilon(E) vs x(amide).

Journal Article↗