Amide Analogues Research Articles

Hepatic sn-glycerol-3-phosphate acyltransferases: Effect of monoacylglycerol analogs on mitochondrial and microsomal activities

The regulation of cellular diacylglycerol levels may have important consequences for protein kinase C activity. Because monoacylglycerols were said to inhibit the committed step of glycerolipid synthesis, the sn-glycerol-3- p acyltransferase (glycerol- P acyltransferase), we determined (1) whether both the mitochondrial and the microsomal glycerol- P acyltransferase isoenzymes were inhibited by 1- and 2-mono-18:1-glycerols and their ether and amide analogs and (2) what the mechanism of inhibition was. 1- and 2-mono-18:1-glycerols, their ether and amide analogs, and l-mono-18:1-glycerol 3-phosphate were all competitive inhibitors of the microsomal glycerol- P acyltransferase activity. The relative K i values suggested that inhibition was strongest with the radyl group at the sn-1 position and that an oxygen bond is important at the sn-1 position. Although the monoacyl- and monoalkylglycerols were also competitive inhibitors of the mitochondrial glycerol- p acyltransferase, neither of the amide analogs was an inhibitor, suggesting that an oxygen bond is essential at both the sn-1 and sn-2 positions. Because monoradylglycerols inhibit several enzyme activities that contribute to the biosynthesis or the metabolism of diacylglycerol, these inhibitors may function within cells in part to regulate cellular diacylglycerol levels.

Probing the Mechanisms of Macromolecular Recognition: the Cytochrome b 5 -Cytochrome C Complex

The specificity of complex formation between cytochrome b5 (cyt b5) and cytochrome c (cyt c) is believed to involve the formation of salt linkages between specific carboxylic acid residues of cyt b5 with lysine residues on cyt c. Site-directed mutagenesis was used to alter the specified acidic residues of cyt b5 to the corresponding amide analogues, which resulted in a lower affinity for complex formation with cyt c. The dissociation of the complex under high pressure resulted in specific volume changes, the magnitude of which reflected the degree of solvation of the acidic residues in the proposed protein-protein interface.

ChemInform Abstract: Amino Acid Derivatives that Stabilize Secondary Structures of Polypeptides. Part 3. β‐Enaminonitriles as Analogs of Secondary Amides. The Mcc Group. 1‐Acylamino‐2‐aminoalkyl‐3‐cyano‐2‐cyclopentenes as Amino Acid Analogs.

AbstractCyclization of the ω‐cyano‐α‐aminocarboxylate (I) yields the aminocyanocyclopentanone (II) which is coupled with amino acid esters (III), forming rigid enamines (IV).

Steroidal pure antioestrogens.

The effects of some novel 7 alpha-alkyl amide analogues of oestradiol on the rat and mouse uterus have been measured. The compound ICI 164,384 [N-n-butyl-N-methyl-11-(3,17 beta-dihydroxyoestra-1,3,5(10)-trien-7 alpha-yl) undecamide] was entirely devoid of oestrogenic activity in the rat and mouse uterus but completely blocked the uterine stimulatory effects of oestradiol and of tamoxifen. Biological activity was confined to 7 alpha-isomers. The affinity of ICI 164,384 for the rat uterus oestrogen receptor (0.19) was substantially greater than that of tamoxifen (0.025 c.f. oestradiol = 1). The compound inhibited oestradiol-induced growth of ZR-71-1 cells in a dose-dependent manner in vitro. ICI 164,384 thus has the characteristics of a pure antagonist of oestrogen action.

Amino acid derivatives that stabilized secondary structures of polypeptides—III. β-Enaminonitriles as analogs of secondary amides. The MCC group—1-acylamino-2-aminoalkyl-3-cyano-2-cyclopentenes as amino acid analogs.

The properties of β-cyanoenamines as analogs of amides are studied with derivatives of a rigid amino acid equivalent—Mcc = 1,2-diamino-3-cyanocyclopentene, prepared in two steps from methyl 2-(N-Boc-amino)-5-cyanopentanoate. Racemation of Mcc and incorporation into a cyclic pentapeptide are described.

Phospholipase A2 mechanism: Inhibition and role in arachidonic acid release

AbstractThe role of phospholipases in cellular activation and arachidonic acid production for prostaglandin and leukotriene biosynthesis is reviewed. Particular emphasis is placed on the function of phospholipase A2 in the processes. The experimental basis of our current state of knowledge of the mechanism of action of the pure, extracellular phospholipase A2 is considered in detail. Experimental approaches dealing with lipid activation, surface dilution kinetics, and enzyme aggregation are considered, and the “dual phospholipid model” for phospholipase A2 action at the lipid/water interface is described in detail. The kinetic analysis of phospholipase A2 inhibitors, including p‐bromophenacylbromide, manoalide, and an alkylether amide analogue of phosphatidylcholine, is considered in light of this model.

ChemInform Abstract: Irreducible Analogues of Mevaldic Acid Coenzyme A Hemithioacetal as Potential Inhibitors of HMG‐CoA Reductase. Part 2. Synthesis of a Secondary Alcohol Analogue of Mevaldic Acid Pantetheine Hemithioacetal and an Amide Analogue of 3‐Hydroxy‐3‐methylglutaryl‐S‐pantetheine.

AbstractAls nicht‐weiterreduzierbare Analoga zur Teilstruktur (Ia) des Mevaldinsäure‐Coenzym A‐Hemiacetals werden die Verbindungen (Ib) und (Ic) hergestellt, die nur schwache Wirkung als HMG‐CoA‐Reduktase‐ ‐Inhibitoren zeigen.

Thioamide substrate probes of metal-substrate interactions in carboxypeptidase a catalysis

Three thioamide peptides in which the oxygen atom of the scissile peptide bond is replaced by sulfur (denoted by ( = S)) were synthesized and found to be good, convenient substrates for carboxypeptidase A. The thioamide bond absorbs strongly in the ultraviolet region, and enzymatic hydrolysis is monitored easily using a continuously recording spectrophotometric assay. The reaction follows Michaelis-Menten kinetics with K cat values of 68, 9.0, and 3.7 sec −1 and K m values of 0.83, 0.81, and 0.53 mM for Z-Ǧlu-Phe(=S)-Phe, Z-Gly-Ala(=S)-Phe, and Z-Phe( = S)-Phe, respectively. Activities of the thioamides and their oxygen amide analogs were determined with a series of metal-substituted carboxypeptidases. The Cd(II), Mn(II), Co(II), and Ni(II) enzymes exhibit 30%–35%, 60%–85%, 150%–190%, and40%–55% of the Zn(II) enzyme activity with the amide substrates; this compares with 240%–970%, 0%–15%, 340%–840%, and 30%–140% of the Zn(II) activity, respectively, with the thioamides. The activity of the Cu(II) and Hg(II) enzymes is less than 3% toward all substrates. Cadmium, a thiophilic metal, yields an enzyme which is exceedingly active with the thioamides; the k cat K m values are 2.4–9.7-fold higher than with Zn(II) carboxypeptidase. In contrast, Mn(II), which has a relatively low affinity for sulfur, yields an enzyme with correspondingly low activity toward the thioamides. The results are consistent with a mechanism for peptide bond hydrolysis in which the metal atom interacts with the substrate carbonyl atom during catalysis.

Design and biological activity of analogs of growth hormone releasing factor with potential amphiphilic helical carboxyl termini.

A 29-amino acid analog of growth hormone releasing factor (GHRF) was designed in which the sequence of the first six amino acids at the amino terminus was maintained while the postulated amphiphilic helical structure in the remainder of the molecule was optimized. The amino acid sequence of the analog differed from that of the first 29 residues of human GHRF by 13 residues. The peptide was synthesized by the solid-phase procedure in amide and free acid forms, both of which were tested for biological activity. When assayed for the ability to stimulate growth hormone secretion in primary cultures of rat anterior pituitary cells, the amide analog was 1.57 times as potent as GHRF-(1-40)-OH, which was used as the standard for comparison, while the free acid form was 1/6th as potent in the same assay. The two forms of the analog were also tested for stimulation of cAMP formation; they exhibited relative potencies similar to those observed for growth hormone secretion. The high activity of the analog provides good evidence for the importance of an amphiphilic helical structure in the carboxyl-terminal portion of the GHRF molecule.

Acyltransferase Activity of the Wide Spectrum Amidase of Brevibacterium sp. R312

Summary: The wide spectrum amidase from Brevibacterium sp. R312, which can hydrolyse many amides tothe corresponding acids, was shown to transfer the acyl groups of amides, acids and esters to hydroxylamine. The transfer rates ofthese reactions in cytoplasmic fractions were measured and compared. The K m and V max were determined for different substrates in the presence of hydroxylamine. The enzyme was also shown to transfer the acyl group of the amide analogue N–methylacetamide to hydroxylamide and that of acetamide to the hydroxylamine analogue methylhydroxylamine.

Production and Characterization of Growth Hormone Releasing Factor Analogs Through Recombinant DNA and Chemical Techniques

A growth hormone releasing factor analog [Leu27,Hse44]GRF(1–44)lactone has been made by recombinant DNA techniques. The peptide was expressed from a multiple–copied GRF gene fused to lacZ. The monomeric GRF peptide analog with a C–terminal homoserine lactone was obtained upon treatment of the isolated fusion protein with cyanogen bromide. The yield of the analog increased with the number of copies fused to β–galactosidase. The C–terminal homoserine moiety was chemically converted to the primary amide, [Leu27,Hse44]GRF(1–44)NH2 and also the n–butyl and n–dodecyl amides, [Leu27, Hse44]GRF(1–44)NHC4H9 and [Leu27,Hse44]GRF(1–44)NHC12H25. The primary amide exhibited a slightly higher releasing activity than the naturally occurring hpGRF(1–44)NH2 whereas the secondary amide analogs had lower activities.

Irreducible analogs of mevaldic acid coenzyme A hemithioacetal as potential inhibitors of HMG-CoA reductase. 2. Synthesis of a secondary alcohol analog of mevaldic acid pantetheine hemithioacetal and an amide analog of 3-hydroxy-3-methylglutaryl-S-pantetheine

Synthese de l'acide [dihydroxy-3,5 methyl-3 pantothenoylamino]-8-caprylique et du pantothenoylamide de l'acide (hydroxy-3 methyl-3) glutarique

ChemInform Abstract: Insect Juvenil Hormone Analogues. Part 23. Synthesis of Some Functionalized Analogues of Long Chain Aliphatic Acid Amides and Their Juvenile Hormone Activity.

AbstractDie Geranylcarbonsäuren (I) liefern mit primären Aminen (II) die Amide (III), die sich mit m‐Chlorperbenzoesäure zu den Epoxiden (IV) bzw. Sulfoxiden (V) oxidieren lassen.

Regulation of nitrile-hydratase synthesis in a Brevibacterium species.

The regulation of nitrile-hydratase biosynthese was studied in Brevibacterium sp R 312. Enzyme biosynthesis was not influenced by any carbon and nitrogen source used in the growth medium. It was, however, repressed by amide and amide analogues. Acetamide repressed nitrile-hydratase biosynthesis and induced the wide-spectrum amidase. Therefore, it appeared reasonable to hypothesize a single repressor gene for the nitrile-hydratase/wide-spectrum amidase system.

Does growth hormone releasing factor desensitize the somatotroph? Interpretation of responses of growth hormone during and after 10-hour infusion of GRF 1-29 amide in man.

It is unclear whether growth hormone releasing factor (GRF) administration in vivo may desensitize the somatotroph. To investigate this possibility we have examined the effects of 10-h infusion of the equipotent 1-29 amide analogue of hpGRF on serum GH levels and on the subsequent GH response to a bolus dose of GRF (1-29). Four normal adult males received an intravenous infusion of 1-29 GRF (1 microgram/kg/h) from 0800 to 1800 h, with blood samples taken at 10 min intervals. A 100 micrograms intravenous bolus dose of GRF was given at 1800 h, and sampling continued for a further 90 min. GH levels were near or below the limit of detection (0.5 mU/l) throughout the control 10 h period. During GRF infusion there was increased GH release with pulses of irregular frequency and amplitude (up to 80 mU/l) continuing throughout the entire infusion period. There was no apparent reduction in total GH released towards the latter part of the infusion. On the control day, 100 micrograms GRF bolus increased mean (+/- SEM) GH from 0.82 +/- 0.21 mU/l to a peak of 59.0 +/- 44.8 mU/l (P less than 0.002). Following 10-GRF infusion, responses to bolus injection of GRF were reduced, but variable. In two subjects a small rise in GH levels occurred (basal 6.4 and 7.2 rising to peak values of 11.2 and 23.0 mU/l respectively). In the other two subjects, GH levels fell but in these the GRF bolus had coincided with a GH peak. The loss of GRF responsiveness after GRF infusion may be due to 'desensitization'.(ABSTRACT TRUNCATED AT 250 WORDS)

Phosphono-platelet activating factor. II. Synthesis of 2-acetamido-2-deoxy-1- O-octadecylglycerol-3-(2-trimethylammoniumethyl) and (2-aminoethyl)phosphonates

The chemical synthesis of the amide analogs of 1- O-alkyl-2- O-glyceryl-3- O-phosphoryl choline as its phosphono analog (phosphono-AGEPC) and 1- O-alkyl-2- O-acetyl-glyceryl-3- O-phosphoryl ethanolamine as its phosphono analog (phosphono-AGEPE) is reported. The intermediate acetamides for the subsequent phosphonylations were obtained (i) by classical organic reactions and (ii) by the method of Chandrakumar and Hadju (Tetrahedron Lett., 23 (1982) 1043–1046). Phosphonylation for the choline analog was accomplished with 2-bromoethyl phosphonic acid monochloride in anhydrous and ethanol-free chloroform in the presence of triethylamine. This was followed by reaction with anhydrous trimethylamine in dimethylformamide in a sealed tube at 50–55°C for 3 days. Phosphonylation for the ethanolamine analog was accomplished with 2-pinthalimidoethyl-phosphonic acid monochloride in anhydrous and ethanol-free chloroform in the presence of anhydrous triethylamine, followed by hydrazinolysis in 90% ethanol under reflux for 4 h. The products were identified by elemental analysis, thin-layer chromatography (TLC) and IR spectroscopy.

Ammonia and methane chemical ionization mass spectra of methotrexate and its amide and ester analogues

The use of chemical ionization mass spectrometry for the characterization of analogues of methotreate, N-[4-[[(2,4-diamino-6-pteridinyl)methyl]amino]benzoyl]-L-glutamic acid, has been studied. With methane as reactant gas, abundant [MH]+ ions were generally not produced. However, with ammonia, especially in conjunction with thermal desorption from a platinum wire, significant amounts of [MH]+ ions were formed by methotrexate, the α-, γ- and diamide analogues, and series of α- and γ-monoalkylamide derivatives. The t-butyl esters of the various monoamides behaved similarly to the corresponding monoamides, except for the ready loss of isobutylene. Fragment ions from both methane and ammonia chemical ionization were formed by cleavages ‘benzylic’ to the pteridine ring, by bond breakage at the amide bond between the aminobenzoyl and glutamyl moieties, and by fragmentations on both sides of this amide bond. Fragment ions from these processes, in conjunction with further disintegration of the glutamyl moiety, are diagnostic of the pteridine, aminobenzoyl and glutamyl moieties of the analogues. Examples of application to structural determination are given.

Multiple-copy genes: production and modification of monomeric peptides from large multimeric fusion proteins

A vector system has been designed for obtaining high yields of polypeptides synthesized in Escherichia coli. Multiple copies of a synthetic gene encoding the neuropeptide substance P (SP) (Arg-Pro-Lys-Pro-Gln-Gln-Phe-Phe-Gly-Leu-Met-NH 2) have been linked and fused to the lacZ gene. Each copy of the SP gene was flanked by codons for methionine to create sites for cleavage by cyanogen bromide (CNBr). The isolated multimeric SP fusion protein was converted to monomers of SP analog, each containing a carboxyl-terminal homoserine lactone (Hse-lactone) residue (Arg-Pro-Lys-Pro-Gln-Gln-Phe-Phe-Gly-Leu-Hse-lactone), upon treatment with CNBr in formic acid. The Hse-lactone moiety was subjected to chemical modifications to produce an SP Hse amide. This method permits synthesis of peptide amide analogs and other peptide derivatives by combining recombinant DNA techniques and chemical methods.

Evaluation of the biological properties of parathyroid hormone and analogues in a vascularly isolated parotid gland-based assay.

Infusion of bovine parathyroid hormone (bPTH) preparations into the arterial blood supply of the vascularly isolated parotid gland in anaesthetized sheep increases salivary phosphate concentration and gland blood flow rate with rapid onset and offset of action. These responses have been used as a bioassay for PTH and PTH analogues and for assessing the properties of an in-vitro inhibitory analogue [Nle-8, Nle-18, Tyr-34]bPTH-(3-34)amide. [Nle-8, Nle-18, Tyr-34]bPTH-(1-34)amide at 10(-9) to 10(-8) mol/l was four to five times more potent than bPTH(1-34) on both salivary phosphate and blood flow assays. Human PTH(1-34) was not significantly more potent than bPTH(1-34). The [Nle-8, Nle-18, Tyr-34]bPTH-(3-34)amide analogue had very slight agonist activity at 3 X 10(-7) mol/l and at a 100:1 ratio of analogue to PTH it completely inhibited the action of bPTH(1-34) on phosphate secretion and gland blood flow. It caused partial inhibition at 10:1 and had no evident effect at 1:1. These results differ from previous in-vitro results and indicate that the preparation may be valuable for evaluation of agonist and antagonist analogues of PTH. The vascularly isolated parotid gland of the sheep permits repeated random testing of analogues in a control-test-control sequence and the results indicate high sensitivity to PTH in a rapidly reactive in-vivo system with two responding parameters.

Influence of pyrethroid ester, oxime ether, and other central linkages on insecticidal activity, hydrolytic detoxification, and physicochemical parameters

The relative potency to target and nontarget insects of ester pyrethroids and the analogous oxime ethers, and the degree of synergism of the esters with tributyl phosphorotrithioate, provide a useful guide to the importance of esterase detoxification in species specificity. These criteria indicate that esterase detoxification is a more important component of pyrethroid tolerance in Chrysopa carnea and Cryptolaemus montrouzieri larvae than in Exochomus flavipis larvae and Musca domestica adults. Studies with 3-phenoxybenzyl 2-(4-chlorophenyl)-2-cyclopropylacetate and the corresponding 2,3,4,5,6-pentafluorobenzyl ester, their oxime ether analogs, and permethrin and its thiol ester and amide analogs provide evidence that the high insecticidal activity of some ester and E-oxime ether pyrethroids, relative to that of the corresponding thiol ester and amide, is more closely associated with the dipole moment and polarizability of the central linkage and its resistance to esterase detoxification than with bond lengths or lipophilicities conferred by a specific linkage. Pentafluorobenzyl tetramethylcyclopropanecarboxylate is very effective in the vapor state for house fly control.