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PubMed1975

Cytotoxicity of carcinogenic aromatic amides in normal and xeroderma pigmentosum fibroblasts with different DNA repair capabilities.

The effect of exposure to UV irradiation or to the N-acetoxy-ester derivatives of four carcinogenic aromatic amides, 4-acetylaminobiphenyl (AABP), 2-acetylaminofluorene (AAF), 2-acetylaminophenanthrene, and 4-acetylaminostilbene, on cell survival was compared in strains of cultured human fibroblasts possessing normal rates of excision repair of DNA and in three strains of xeroderma pigmentosum (XP) cells, each differing in its rate of excision repair. The survival of each strain after exposure to UV reflected its capacity to repair DNA. Thus the slope of the survival curve for the XP strain with the poorest capacity for excision repair (XP12BE complementation group A) was 5.8-fold steeper than the exponential portion of the curve for the normally repairing strains; that of XP2BE (complementation group C) was 1.95-fold; and that of XP4BE (a variant capable of a normal rate of dimer excision) was only 1.3-fold steeper. The slope of the survival curves after exposure to each N-acetoxy ester derivative for these same XP strains averaged 6.4, 2.0, and 1.4 times steeper, respectively, than that of the normal strains tested. The excision repair capacity of these lines after exposure to N-acetoxy-AAF (50 muM/ml) was tested with alkaline cesium chloride density gradient centrifugation to detect incorporation of tritiated thymidine into nonreplicated DNA. The normal strains and XP4BE exhibited DNA excision repair by this method, whereas XP patients 2 and 12 did not. The cytotoxic effect of the four parent aromatic amide carcinogens, their N-hydroxy derivatives, as well as the N-acetoxy ester of each of the four N-hydroxy compounds and the N-sulfate ester of N-hydroxy-AAF and N-hydroxy-AABP in the XP2BE strain, was compared with their effect on the normal fibroblasts. The parent amides proved to be noncytotoxic at all doses tested. In contrast, the N-hydroxy derivatives of each aromatic amide were highly cytotoxic, as were the ester compounds. For each active derivative, the slope of the survival curve for XP2BE was 2-2.k times steeper than that of the normally repairing strain.

2-Acetylaminofluorene↗
PubMed1975

[Synthesis of virostatically acting N[adamantyl-(1)]-carbonic acid amides].

By introduction of carboxylic acid amide groupings into 1-amino-adamantant (I), remarkable virustatic effects have been obtained, particularly which N-(1-adamantyl) cinnamic acid amide (VIIa) and N-(1-adamantyl)-3-(4'-methoxyphenyl)-acrylic acid amide (VIIc). The synthesis of the N-(1-adamantyl)-carboxylic acid amides (IV, VII, X) could be reallzed by interaction of I with carboxylic acids (II, V, VIII) via the carboxylic acid chlorides (III, VI, IX), the latter not being isolated for the simplification of the process.

Adamantane↗
PubMed1979

Analyses of infrared amide bands of chitin.

Infrared spectra of chitin isolated from various biological species were measured by Fourier transform technique. The recorded spectra were decomposed into component bands within 1500--1750 cm-1 and 3000--3500 cm-1 spectral regions; it allowed us to establish the precise position of amide I and amids II bands. It was shown that the positions of amide I and amide II bands are independent of the source from which chitin was isolated.

Amides↗
PubMed1978

Amide proton spin-lattice relaxation in polypeptides. A field-dependence study of the proton and nitrogen dipolar interactions in alumichrome.

The proton nuclear magnetic resonance (NMR) spin-lattice relaxation of all six amides of deferriferrichrome and of various alumichromes dissolved in hexadeutero-dimethylsulfoxide have been investigated at 100, 220, and 360 MHz. We find that, depending on the type of residue (glycyl or ornithyl), the amide proton relaxation rates are rather uniform in the metal-free cyclohexapeptide. In contrast, the (1)H spinlattice relaxation times (T(1)'s) are distinct in the Al(3+)-coordination derivative. Similar patterns are observed in a number of isomorphic alumichrome homologues that differ in single-site residue substitutions, indicating that the spin-lattice relaxation rate is mainly determined by dipole-dipole interactions within a rigid molecular framework rather than by the specific primary structures. Analysis of the data in terms of (1)H-(1)H distances (r) calculated from X-ray coordinates yields a satisfactory linear fit between T(1) (-1) and Sigmar(-6) at the three magnetic fields. Considering the very sensitive r-dependence of T(1), the agreement gives confidence, at a quantitative level, both on the fitness of the crystallographic model to represent the alumichromes' solution conformation and on the validity of assuming isotropic rotational motion for the globular metallopeptides. An extra contribution to the amide proton T(1) (-1) is proposed to mainly originate from the (1)H-(14)N dipolar interaction: this was supported by comparison with measurements on an (15)N-enriched peptide. The nitrogen dipolar contribution to the peptide proton relaxation is discussed in the context of {(1)H}-(1)H nuclear Overhauser enhancement (NOE) studies because, especially at high fields, it can be dominant in determining the amide proton relaxation rates and hence result in a decreased effectiveness for the (1)H-(1)H dipolar mechanism to cause NOE's. From the slope and intersect values of T(1) (-1) vs. Sigmar(-6) linear plots, a number of independent estimates of tau(r), the rotational correlation time, were derived. These and the field-dependence of the T(1)'s yield a best estimate approximately 0.37 ns, in good agreement with 0.38 ns [unk] [unk] 0.41 ns, previously determined from (13)C and (15)N spin-lattice relaxation data.

Aluminum↗
PubMed1975

Cardiorenal effects of lidocaine and procaine amide in the conscious dog.

Simultaneous measurements of hemodynamics, arterioventricular (AV) conduction, and renal functioner were obtained in conscious dogs. Catheters were implanted for the long-term measurement of central aortic, right ventricular, and pulmonary artery pressure. AV conduction was assessed following surgical implantation of multipolar electrode plaques in the area of the bundle of His, as well as on the epicardium of the right and left atria and ventricles. Renal function was assessed utilizing standard techniques. Following control measurements, lidocaine, 1 mg/kg, or procaine amide, 10 mg/kg, was administered intravenously. Subsequently, serial measurements were obtained for a 90-min period. No significant changes in hemodynamics were observed following either drug. Procaine amide produced a significant increase in heart rate and a minimal increase in QRS duration associated with a decrease in low right atrial to His bundle conduction time. However, no significant changes in cardiac conduction were observed after lidocaine administration. Renal function was unaffected by lidocaine but significantly depressed by procaine amide, as demonstrated by a decrease in GFR and effective renal flow. In summary, acute administration of procaine amide significantly alters renal function in the conscious dog with minimal effects on AV conduction and hemodynamics.

Aminohippuric Acids↗
PubMed1979

Characteristics of lithium iodide-containing poly(ethylene glycol) as a gas chromatographic stationary phase, and its application to analysis of amidic drugs.

The characteristics of lithium iodide-containing poly(ethylene glycol) as a gas chromatographic stationary phase have been evaluated in terms of partial free energy of transfer (delta G t0) from poly(ethylene glycol) to the lithium iodide-poly(ethylene glycol) system for a variaty of amides (n-fatty acid amides, lactams, benzamides, anilides, nicotinamides, isonicotinamides, barbiturates, pyrazolones) and several amines. The changes in relative retention and resolution of two solute peaks caused by the addition of lithium iodide to poly)ethylene glycol) are correlated with the difference in their delta Gt0 values. The application to the specific separation of some amidic drugs is demonstrated.

Amides↗
PubMed1992

Redox-dependent changes in beta-extended chain and turn structures of cytochrome c in water solution determined by second derivative amide I infrared spectra.

The redox-dependent changes in secondary structure of cytochromes c from horse, cow, and dog hearts in water at 20 degrees C have been determined by amide I infrared spectroscopy. Second derivative amide I spectra were obtained by use of a procedure that includes a convenient method for the effective subtraction of the spectrum of water vapor in the system. The band at 1657 cm-1 representing the helix structure was unaffected by a change in redox state whereas changes in bands due to turns at 1680, 1672, and 1666 cm-1, unordered structure at 1650 cm-1, and beta-structures at 1632 and 1627 cm-1 occurred. About one-fourth of the beta-extended chain spectral region and one-fifth of the beta-turn region (involving a total of approximately 9-13 residues) were sensitive to the oxidation state of heme iron. No significant changes in the secondary structure of either the reduced or oxidized protein due to changes in ionic strength were detected. The localized structural rearrangements triggered by the changes in oxidation state of heme iron are consistent with differences in the binding of heme iron to a histidine imidazole nitrogen and a methionine sulfur atom from the beta-extended chain. The demonstrated ability to obtain highly reproducible second derivative amide I infrared spectra confirms the unique utility of such spectral measurements for localization of subtle changes in secondary structure within a protein, especially for changes among the multiple turns and beta-structures.

Amides↗
PubMed1975

Structure-activity correlations among rifamycin B amides and hydrazides.

Structure-antibacterial activity correlation equations have been developed for aseries of 44 amides and 25 hydrazides of rifamycin B in five bacterial systems. The best amide equations show that activity is a parabolic function of log P. A wide variation in log Po was found for the various bacterial systems. The most important correlation parameter in the hydrazide equations is omicron*. The significance of this finding is somewhat obscured by the high degree of collinearity among the parameters evaluated (omicron*, E-s, log P). Two rifamycin B amides were prepared and evaluated as a result of this study. The correlation equations quantitatively predicted their activity in five of six tests.

Amides↗
PubMed1978

Three neurotoxins from the venom of a sea snake Astrotia stokesii, including two long-chain neurotoxic proteins with amidated C-termini.

From the venom of a sea snake Astrotia stokesii three neurotoxic components, toxins Astrotia stokesii a, b and c were isolated in 40, 15 and 5% yield by weight respectively of the whole venom. Their LD50 values for 20g mice were 0.13, 0.096 and 0.098 microgram/g body wt. respectively and accounted for almost all the lethal activity of the venom. Their amino acid sequences were determined. Astrotia stokesii a was composed of 60 amino acid residues with nine half-cystine residues and was quite homologous to other sea-snake short-chain neurotoxins in its amino acid sequence. Toxins Astrotia stokesii b and c were composed of 70 and 72 amino acid residues respectively with 10 half-cystine residues. They are the first long-chain neurotoxins with high activity isolated from sea-snake venoms. The C-terminal carboxy groups of toxins b and c were found to be amidated; the amidation is known for some polypeptides, but is novel for a protein. The amide group may make a hydrogen-bond with glutamic acid-39, which replaces a lysine that has so far been found invariably in long-chain neutrotoxins. Astrotia stokesii b and c are also novel in having phenylalanine-25 and isoleucine- or valine-42. The ordinary Tyr-Glu pair, which is observed in X-ray structure [Low, Preston, Sato, Rosen, Searl, Rudko & Richardson (1976) Proc. Natl. Acad. Sci. U.S.A. 73, 2991-2994] and n.m.r.study [Inagaki, Tatsumi, Miyazawa, Hori & Tamiya (1977) Abstr. Int. Congr. Pure Appl. Chem. 26th, p. 336] on erabutoxins may be replaced by a hydrophobic pair. Detailed evidence for the amino acid sequences of the proteins has been deposited as Supplementary Publication SUP 5009o (30 pages) at the British Library Lending Division, Boston Spa, Wetherby, West Yorkshire LS23 7B1, U.K., from whom copies can be obtained on the terms indicated in Biochem. J. (1978) 169, 5.

Amides↗
PubMed1978

Free radicals in U.V.-irradiated aqueous solutions of substituted amides: an e.s.r. and spin-trapping study.

The radicals produced by reactions of hydroxyl radicals with alkyl substituted ureas and amides in aqueous solutions have been investigated. Hydroxyl radicals were produced by U.V. photolysis of H2O2 and the short-lived amide and urea radicals were spin-trapped by t-nitrosobutane and identified by e.s.r. For all N-alkyl derivatives of urea and acetamide, and for N,N-dimethyl propionamide and N,N-diethyl formamide, only radicals centred on N-alkyl groups were detected. Radicals situated only on alkyl groups attached to the carbonyl carbon were observed for dimethyl acetamide, trimethyl acetamide and butyramide. However, for N,N-dimethyl butyramide, N, N-diethyl butyramide, N-methyl propionamide and N, N-diethyl propionamide, free radicals were formed which were localized on the alkyl group attached to the amide carbon as well as those attached to nitrogen. The hydrogen atom bound to the carbonyl carbon was abstracted in N-ethyl formamide. Acyl radicals formed by C-N scission due to direct U.V. photolysis of N, N-dimethyl butyramide and N,N-dimethyl propionamide were also detected.

Acetamides↗
PubMed1978

Specific modification of the properties of the N-hydroxylase. Relationship with carcinogenesis by aromatic amides.

N-hydroxylation represents the first and limiting step in the metabolic pathway leading to the carcinogenic activity of aromatic amines and amides. Using a method recently developed by the same authors (Analytical Biochemistry, in press), the effects of pretreatment of male adult rats with N-2-acetylaminofluorene (2AAF), N-4-acetylaminofluorene (4AAF), N-4-acetyl-aminobiphenyl, (4-AABP), and phenobarbital (PB), on the kinetic parameters of the N-hydroxylase activity have been evaluated and compared. Our resutls clearly demonstrate that both hepatocarcinogenic amides, 2-AAF and 4-AABP very significantly increase the affinity of the activating enzyme towards both substrates; on the other hand, 4-AAF and PB, which are non-carcinogenic compounds slightly decrease the affinity of the enzyme. In conclusion, the carcinogenic aromatic amides seem to specifically modify the catalytic properties of the enzyme responsible for their own metabolic activation.

2-Acetylaminofluorene↗
PubMed1977

Hydrolysis of alkyl ester and amide substrates by papain.

The ratio of the rate constants of acylation of papain with some amino acid ester and amide substrates is unexpectedly low. The contribution to this low ratio by the N-acyl group and the amino acid side chain was studied by measuring the rate constants of substrates containing various acyl groups (benzoyl and benzyloxycarbonyl) and various side chains (glycine, alanine, norleucine, citrulline and arginine). The benzoyl esters were found to be less reactive than the corresponding benzyloxycarbonyl esters, whereas the benzoyl and corresponding benzyloxycarbonyl amides reacted with papain at similar rates. These findings can be explained by the dominance of hydrogen bond formation between the enzyme and amide substrates, which comprensates for the less favourable binding of the benzoyl group. It is also apparent from the similar acylation rate constants for norleucine, citrulline and arginine derivatives that the guanidyl group only slightly affects the reaction of arginine derivatives with papain.

Acylation↗
PubMed1978

[Synthesis of human [11-leucine]minigastrin I--II. Purification of the synthetic tridecapeptide amide and isolation of a side-product (author's transl)].

The preparation of the pure 11-leucine analogue of human minigastrin I, a linear tridecapeptidaemide with full "gastrin activity", from the crude synthetic material obtained after deblocking of the overall protected tridecapeptide amide derivative by means of trifluoroacetic acid, is achieved by ion-exchange chromatography on DEAE-Sephadex A-25 and subsequent partition chromatography on Sephadex G-25. The isolation of a synthetic side-product and its identification as human [10-(Nin-tert-butyl-tryptophan),11-leucine]minigastrin I by means of spectroscopic (UV, fluorescence, 1H-NMR, MS), enzymatic and chromatographic methods is described. The pure tridecapeptide amides human [Leu11]minigastrin I and human [Trp(1'-But)10,Leu11]minigastrin I are isolated in overall yields of 37.4% and 4.6%, respectively (mol-% with regard to the overall protected tridecapeptide amide derivative).

Amides↗
PubMed1978

[N,N-Di-(1-ethylpropyl)amides of benzoic and naphthoic acids having phytotoxic activity].

N,N-di-(1-ethylpropyl)amides of benzoic and naphthoic acids suitable substituted in the nucleus were prepared and tested for selective phytotoxic activity in both pre- and post-emergence tests against some weed species. All the amides tested showed good generic phytotoxicity, often with good selectivity, on absorbance through the roots of graminaceous weeds. The nature and degree of phytotoxic activity was influenced by the nature, position and number of substituents on the aromatic nucleus. Confirmation was again obtained of the importance of alpha-substitution in the two alkyl substituents on the amide nitrogen in producing selective phytotoxic activity.

Amides↗
PubMed1977

[Study on the amide of 2-chlorobornan-4-carboxylic acid].

During the study of the transpositions undergone by the amide of canphen-4-carboxylic acid on treatment with concentrated hydrochloric acid, the formation of the amide of 2-chlorobornan-4-carboxylic acid alone, arising in two polymorphous forms, has been confirmed. Its reduction produced 2-chloro-4-aminomethylbornane; the detachment of hydrochloric acid at the amide of canphen-1-carboxylic acid.

Amides↗
PubMed1992

Effects of DNA binding and metal substitution on the dynamics of the GAL4 DNA-binding domain as studied by amide proton exchange.

Backbone amide proton exchange rates in the DNA-binding domain of GAL4 have been determined using 1H-15N heteronuclear correlation NMR spectroscopy. Three forms of the protein were studied-the native Zn-containing protein, the Cd-substituted protein, and a Zn-GAL4/DNA complex. Exchange rates in the Zn-containing protein are significantly slower than in the Cd-substituted protein. This shows that Cd-substituted GAL4 is destabilized relative to the native Zn-containing protein. Upon DNA binding, global retardation of amide proton exchange with solvent was observed, indicating that internal fluctuations of the DNA-recognition module are significantly reduced by the presence of DNA. In all forms of the protein, the internal dyad symmetry of the DNA-recognition module of GAL4 is reflected by the backbone amide proton exchange rates.

Amino Acid Sequence↗
PubMed1975

Acetylation of procaine amide in man. A preliminary communication.

The metabolism of procaine amide was studied in 41 cardiac patients who had achieved steady state plasma concentrations of the drug. Acetylated procaine amide accounted for 31 +/- 12% (range 16-63%) of the overall urinary recovery of the drug and is therefore a main metabolite in man. Plasma levels of the metabolite were usually lower but sometimes exceeded those of the parent compound with variations between 1 and 15 mug/ml. The metabolite had a weaker effect than procaine amide on the maximal electrical driving velocity of isolated atrial strips from guinea pig.

Acetylation↗