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PubMed2006

Effect of pectin and amidated pectin on cholesterol homeostasis and cecal metabolism in rats fed a high-cholesterol diet.

Two experiments were performed to compare the effect of pectin and its hydrophobic derivatives on homeostasis of cholesterol and cecal metabolism in male young rats. Control rats were fed a diet supplemented with palm fat and cholesterol (50 and 10 g/kg, respectively). Rats of other groups were fed the same diet containing citrus pectin or octadecylpectinamide (60 g/kg). Diets were fed for 4 weeks. In experiment I, pectinamide of lower degree of amidation (30 %) increased serum HDL cholesterol from 1.20 to 1.43 micromol/ml (p>0.05) at the expense of other cholesterol fractions. In experiment II, pectinamide of a higher degree of amidation (53 %) significantly decreased total serum cholesterol from 2.08 to 1.67 micromol/ml. Amidated pectins at both levels of substitution significantly decreased hepatic concentrations of cholesterol and fat. In both experiments the relative weight of cecum in the pectinamide group was significantly lower than in pectin group. The highest cecal concentrations of short-chain fatty acids (SCFA) were found in rats fed a diet with pectin (133.2 and 129.3 micromol/g in experiment I and II, respectively). In other groups, cecal SCFA was significantly (pectinamide groups) or non-significantly (controls) lower. In wet feces, SCFA concentrations were higher and butyrate molar proportions lower than in corresponding cecal contents. Pectinamide of a lower or higher degree of substitution significantly increased fecal content of cholesterol from 18.5 and 17.3 micromol/g in controls to 31.8 and 28.0 micromol/g, respectively. Corresponding concentrations of coprostanol were decreased. Effects of pectin on cholesterol homeostasis were absent or marginal. Histological examination revealed that hepatic tissue of control and pectin-fed rats was infiltrated with lipids. The Sudan black-positive material was absent in the liver of rats fed pectinamides. No pathological changes of liver tissue were apparent. In summary, hydrophobic amidated pectins significantly altered cholesterol homeostasis in rats and might be considered as a clinically effective hypocholesterolemic agent. Low cecal SCFA concentrations in rats fed pectinamides suggest that amidation of pectin had decreased its fermentability.

Amides↗
PubMed1976

The interaction of salts, amides, and water.

Infrared and Raman spectra are presented for salt solutions in N-methyl formamide and N,N'-dimethylformamide. Viscosities are reported for many of these solutions. Spectroscopic and viscosity data are also given for amide-salt solutions containing water. The three-component systems exhibit a hydrogen-bonding strength of water proton greater than amide proton, and an acceptor strength of Cl- greater than amide carbonyl oxygen greater than water oxygen. The salt cation is deduced by means of viscosity measurements to interact strongly with the amide carbonyl oxygen, even in the presence of appreciable quantities of water. Association of amides by hydrogen bonding through halide ions is also indicated.

Amides↗
PubMed2000

Characterization of the unique function of a reduced amide bond in a cytolytic peptide that acts on phospholipid membranes.

The incorporation of a reduced amide bond, psi(CH(2)NH), into peptide results in an increase in the net positive charge and the perturbation of alpha-helical structure. By using this characteristic of the reduced amide bond, we designed and synthesized novel pseudopeptides containing reduced amide bonds, which had a great selectivity between bacterial and mammalian cells. A structure-activity relationship study on pseudopeptides indicated that the decrease in alpha-helicity and the increase in net positive charge in the backbone, caused by the incorporation of a reduced amide bond into the peptide, both contributed to an improvement in the selectivity between lipid membranes with various surface charges. However, activity results in vitro indicated that a perturbation of alpha-helical structure rather than an increase in net positive charge in the backbone is more important in the selectivity between bacterial and mammalian cells. The present result revealed that the backbone of membrane-active peptides were important not only in maintaining the secondary structure for the interactions with lipid membranes but also in direct interactions with lipid membranes. The present study showed the unique function of a reduced amide bond in cytolytic peptides and a direction for developing novel anti-bacterial agents from cytolytic peptides that act on the lipid membrane of micro-organisms.

Amides↗
PubMed2001

Multiple amidated neuropeptides are required for normal circadian locomotor rhythms in Drosophila.

In Drosophila, the amidated neuropeptide pigment dispersing factor (PDF) is expressed by the ventral subset of lateral pacemaker neurons and is required for circadian locomotor rhythms. Residual rhythmicity in pdf mutants likely reflects the activity of other neurotransmitters. We asked whether other neuropeptides contribute to such auxiliary mechanisms. We used the gal4/UAS system to create mosaics for the neuropeptide amidating enzyme PHM; amidation is a highly specific and widespread modification of secretory peptides in Drosophila. Three different gal4 drivers restricted PHM expression to different numbers of peptidergic neurons. These mosaics displayed aberrant locomotor rhythms to degrees that paralleled the apparent complexity of the spatial patterns. Certain PHM mosaics were less rhythmic than pdf mutants and as severe as per mutants. Additional gal4 elements were added to the weakly rhythmic PHM mosaics. Although adding pdf-gal4 provided only partial improvement, adding the widely expressed tim-gal4 largely restored rhythmicity. These results indicate that, in Drosophila, peptide amidation is required for neuropeptide regulation of behavior. They also support the hypothesis that multiple amidated neuropeptides, acting upstream, downstream, or in parallel to PDF, help organize daily locomotor rhythms.

Amides↗
PubMed1976

Incorporation of intravenously administered urea-15N into sheep plasma proteins and their amide groups.

Two sheep with a low and high nitrogen intake (7.6 and 24 g N/day respectively) were given a single intravenous dose of 15N-labelled urea (15.3 mg 15N/kg b.w.) The findings were as follows. The greater part of non-retained 15N from the administered dose was excreted during the first day after the intravenous administration of 15N-urea. Daily excretion in the faeces amounted to 1.35-2.37% of the 15N in the given dose. With a low N intake, more 15N from the given dose (59.4%) was retained in the N pool than with a high N intake (50.5%). The net passage of 15N into the rumen and 15N incorporation into the amide-N of the plasma proteins was likewise greater. 15N incorporation into the amide-N of the plasma proteins rose steadily for 3 days. The porportion of amidic 15N in the plasma proteins rose steadily for 3 days. The proportion of amidic 15N in the plasma protein total 15N changed on the second and third day after administering 15N-urea from 8% to 16%, with the maximum at the beginning of the second day. The amount of 15N incorporated into the proteins in 1 litre plasma attained up to 3% of the given dose. It is concluded from the results that the synthesis of amino acids and their amide groups is both a quantitatively and a qualitatively important metabolic route for the reutilization of blood urea nitrogen for protein synthesis in ruminants.

Amides↗
PubMed2005

Synthesis and antimelanoma activity of sterically congested tertiary amide analogues of N-acetyl-4-S-cysteaminylphenol.

Interference with the biosynthetic pathway to melanin may be a useful means for developing new chemotherapeutic drugs to combat malignant melanoma. N-Acetyl-4-S-cysteaminylphenol (1) is an analogue of tyrosine that is involved in the pathway to melanin. It is probably oxidized selectively in melanocytes to an o-quinone that can alkylate thiol groups on important cellular enzymes, resulting in interference with cell growth and proliferation. We previously synthesized a range of more lipophilic analogues of 1 by independently varying the acyl portion and introducing substitution alpha to the nitrogen. Most of the new compounds displayed greater cytotoxicity than the original lead compound 1. We also made a series of tertiary amides that again showed higher cytotoxicity than 1. In this work three new acetamides and two new cyclohexanecarboxamides containing 4-S-cysteaminylphenol were prepared incorporating both substitution alpha to the nitrogen and different substituents on the nitrogen of the amide in each compound to increase lipophilicity and to reduce further the possibility of hydrolysis of the amides. Most of the new tertiary amides showed greater cytotoxicity towards five representative melanoma cell lines than the parent secondary amide. The highest cytotoxicity against these five cell lines with IC50 values of 1-15 nicroM, comparable to cisplatin, was observed for N-[2[(4-hydroxyphenyl)thio]-1,1-dimethylethyl]-N-methylcyclohexanecarboxamide (8c). The IC50 values of 14.5 and 5.4 microM for this compound against SK-Mel-24 (not containing tyrosinase) and an ovarian cell line, respectively, suggest that interference with the melanin pathway may not be the only mode of action of this new compound. The cyclohexanecarboxamides were better substrates for mushroom tyrosinase (EC 1.14.18.1) than the acetamides.

Agaricales↗
PubMed1990

Thiol-based inhibitors of mammalian collagenase. Substituted amide and peptide derivatives of the leucine analogue, 2-[(R,S)-mercaptomethyl]-4-methylpentanoic acid.

To define the inhibitory requirements of mammalian collagenase, several N-substituted amide and peptide derivatives of the mercaptomethyl analogue of leucine, 2-[(R,S)mercaptomethyl]-4-methylpentanoic acid (H psi[SCH2]-DL-leucine), were synthesized and tested as inhibitors of pig synovial collagenase with soluble type I collagen as substrate. H psi[SCH2]-DL-leucine (IC50 = 320 microM) was about 10 times more potent than the beta-mercaptomethyl compound, N-acetylcysteine. The amide of H psi[SCH2]-DL-leucine was six times more potent than the parent thiol acid. Aliphatic N-substituted amides were less potent than the unsubstituted amide, whereas the N-benzyl amide was slightly more potent. Dipeptides, particularly those with an aromatic group at P2', were up to 20-fold more potent, while tripeptides with an aromatic L-amino acid at P2' and Ala-NH2 at P3' were up to 2200 times more potent than H psi[SCH2]-DL-leucine. The resolved diastereomers of H psi[SCH2]-DL-Leu-Phe-Ala-NH2 inhibited by 50% at 0.3 and 0.04 microM, respectively. The most potent inhibitor synthesized, an isomer of H psi[SCH2]-DL-Leu-L-3-(2'-naphthyl)alanyl-Ala-NH2, exhibited an IC50 of 0.014 microM, a value about 300 times less than similar thiol-based analogues of the P'-cleavage sequence of type I collagen, H psi[SCH2]-DL-Leu-Ala-Gly-Gln-. These structure-function studies establish within the present series of compounds that the most effective inhibitors of mammalian collagenase are not closely related to the P2'-P3' elements of the cleavage site of the natural substrate but rather have an aromatic group at the P2' position and Ala-NH2 at the P3' position.

Amides↗
PubMed1986

Influence of the amino acid moiety on deconjugation of bile acid amidates by cholylglycine hydrolase or human fecal cultures.

The influence of the chemical structure of the amino acid (or amino acid analogue) moiety of a number of synthetic cholyl amidates on deconjugation by cholylglycine hydrolase from Clostridium perfringens was studied in vitro at pH 5.4. Conjugates with alkyl homologues of glycine were hydrolyzed more slowly as the number of methylene units increased (cholylglycine greater than cholyl-beta-alanine greater than cholyl-gamma-aminobutyrate). In contrast, for conjugates with the alkyl homologues of taurine, cholylaminopropane sulfonate was hydrolyzed slightly faster than cholyltaurine, whereas cholylaminomethane sulfonate was hydrolyzed much more slowly. When glycine was replaced by other neutral alpha-amino acids, rates of hydrolysis decreased with increasing steric hindrance near the amide bond (cholyl-L-alpha-alanine much much greater than cholyl-L-leucine much greater than cholyl-L-valine greater than cholyl-L-tyrosine much greater than cholyl-D-valine). Conjugation with acidic or basic amino acids also greatly reduced the rates of hydrolysis, as cholyl-L-aspartate, cholyl-L-cysteate, cholyl-L-lysine, and cholyl-L-histidine were all hydrolyzed at a rate less than one-tenth that of cholylglycine. Methyl esterification of the carboxylic group of the amino acid moiety reduced the hydrolysis, but such substrates (cholylglycine methyl ester and cholyl-beta-alanine methyl ester) were completely hydrolyzed after overnight incubation with excess of enzyme. In contrast, cholyl-cholamine was not hydrolyzed at all, suggesting that a negative charge at the end of the side chain is required for optimal hydrolysis. Despite the lack of specificity for the amino acid moiety, a bile salt moiety was required, as the cholylglycine hydrolase did not display general carboxypeptidase activity for other non-bile acid substrates containing a terminal amide bond: hippuryl-L-phenylalanine and hippuryl-L-arginine, as well as oleyltaurine and oleylglycine, were not hydrolyzed. Fecal bacterial cultures from healthy volunteers also hydrolyzed cholyl-L-valine and cholyl-D-valine more slowly than cholylglycine, suggesting that cholylglycine hydrolase from Clostridium perfringens has a substrate specificity similar to that of the deconjugating enzymes of the fecal flora. The results indicate that modification of the position of the amide bond, introduction of steric hindrance near the amide bond, or loss of a negative charge on the terminal group of the amino acid moiety of the bile acid conjugate greatly reduces the rate of bacterial deconjugation in vitro when compared to that of the naturally occurring glycine and taurine conjugates.

Amides↗
PubMedDate not supplied

[Effect of starvation on the intensity of proteolysis and amidation of proteins in tissues of rats of different ages].

Rates of autolysis and degree of amidation of tissue proteins were studied in rats under conditions of ageing and after starvation during 7 days. Proteins with decreased content of amide groups accumulated in brain, liver tissues and skeletal muscles. This phenomenon occurred apparently due to decrease in the rate of protein autolysis observed in ageing. In testes, where the rate of protein autolysis was similar both in young and old animals, the protein amidation was not altered on the course of ageing. Under conditions of severe starvation activation of proteolysis was observed in cells. At the same time, the amide content was restored in liver and muscle proteins of old rats up to the level, estimated in tissues of young animals. These data suggest stimulation of selective degradation of the deamidated proteins. The activation of autolysis and normalization of the protein amide groups content were not observed in brain of old animals under conditions of starvation.

Aging↗
PubMed1984

Characterization of a peptide alpha-amidation activity from rat anterior pituitary.

A secretory granule associated enzymatic activity from the rat anterior pituitary that can convert the synthetic peptide D-Tyr-Val-Gly into D-Tyr-Val-NH2 is described. Due to the presence of inhibitory activity in the cytosol and rough endoplasmic reticulum/Golgi apparatus fractions, the alpha-amidation activity is barely detectable in crude rat anterior pituitary homogenates. The alpha-amidation activity was primarily soluble, displayed a pH optimum of about 7.0, and showed a requirement for molecular oxygen. The activity was stimulated 7-fold by the addition of optimal concentrations of copper. Of the cofactors tested, only reduced ascorbate produced a severalfold stimulation of activity. Studies with varied D-Tyr-Val-Gly or varied monoiodo-D-Tyr-Val-Gly demonstrate Michaelis Menten kinetics with indistinguishable kinetic constants for both peptides. Upon addition of ascorbate, the apparent Km and Vmax for the synthetic substrate, as estimated from Lineweaver-Burk and Eadie-Hofstee plots, increased by 30- and 60-fold, respectively. Several alpha-melanotropin- and gamma-melanotropin-related peptides with COOH-terminal glycine residues were effective competitive inhibitors of the reaction while the corresponding alpha-amidated peptides were very poor inhibitors. The rat anterior pituitary alpha-amidation activity appears to be very similar to the alpha-amidation activity in rat intermediate and neural pituitary, and mouse anterior pituitary tumor cells.

Amides↗
PubMed1995

Synthesis and characterization of novel analogs of conjugated bile acids containing reversed amide bonds.

New analogs of amino acid-conjugated bile acids were synthesized in which the amide bond was reversed from its normal configuration. These structural isomers of the beta-alanyl conjugates of cholic acid and ursodeoxycholic acid were synthesized by reaction of succinic anhydride with the 24-nor-23-amine derivatives of cholic acid and ursodeoxycholic acid. The chemical and physical properties of these reverse amide conjugated bile acid analogs were compared with those of the normal glycine and beta-alanine conjugates. The reverse amide analogs comigrated with their isomeric beta-alanine conjugates during thin-layer chromatography using a variety of solvent systems. However, the isomeric pairs could be resolved by reversed-phase high performance liquid chromatography, with the reverse amides having greater retention times compared to the beta-alanine conjugates. Critical micelle concentrations, solubility of undissociated forms, and acid dissociation constants were similar for the isomeric pairs. Significant differences in melting points were observed, however, While the isomeric pairs showed no significant differences in sensitivity to base hydrolysis, the reverse amides were not hydrolyzed by the cholylglycine hydrolase from Clostridium perfringens, even after long incubation periods.

Amides↗
PubMed1994

Cannabinoid receptor binding and agonist activity of amides and esters of arachidonic acid.

The cannabinoid receptor in brain (CB1) specifically binds delta 9-tetrahydrocannabinol, the predominant central nervous system-active component of marijuana. An eicosanoid found in brain, N-(2-hydroxyethyl)arachidonylamide (anandamide), binds to CB1 with similar affinity. This report considers structure-activity requirements for a series of novel amides and rigid hairpin conformations typified by N-(2-hydroxyethyl)prostaglandin amides, assayed with phenylmethylsulfonyl fluoride inactivation of esterases/amidases. Arachidonyl esters were 30-fold less potent than N-(2-hydroxyethyl)arachidonylamide, showing a rank order of potency of methyl = ethyl > propyl = isopropyl. Within the N-(hydroxyalkyl)arachidonylamide series, a one-carbon increase in chain length increased the potency 2-fold, but continued extension decreased affinity. Substituting the amide for the N-(2-hydroxyethyl)amide function produced a 4-fold loss of affinity. The N-(propyl)-, N-(butyl)-, and N-(benzyl)arachidonylamide derivatives exhibited a 3-fold increase, no change, and a 5-fold decrease, respectively, in affinity, compared with N-(2-hydroxyethyl)arachidonylamide. Both the methoxy ether and the formamide derivatives suffered > 20-fold loss of potency, compared with N-(2-hydroxyethyl)arachidonylamide. N-(2-Aminoethyl)arachidonylamide interacted poorly with CB1. At 100 microM, N-(2-hydroxyethyl)amide analogs of prostaglandin E2, A2, B2, and B1 failed to alter [3H]CP55940 binding to CB1. N-(2-Hydroxyethyl)arachidonylamide inhibited adenylate cyclase with lesser potency but with similar efficacy, compared with desacetyllevonantradol. Extending the length of the hydroxyalkyl moiety by one carbon increased the apparent potency by 1 order of magnitude. The N-(propyl) derivative exhibited a 5-fold greater potency than did the N-(2-hydroxyethyl) analog. It appears that the bulk and length of the moiety appended to arachidonic acid are more important determinants of affinity for CB1 than is hydrogen-bonding capability.

Adenylyl Cyclase Inhibitors↗
PubMedDate not supplied

[Amides of simple and complex ethers of glycolic acid--inhibitors of alcohol dehydrogenase in rat and human liver].

Amides of glycolic ethers and esters have been synthesized and studied as the inhibitors of rat and human liver alcohol dehydrogenase. Amides of glycolic ethers inhibit the rat liver alcohol dehydrogenase activity by 50-85%, amides of esters by 10-40%. An analogous regularity has been established for human liver alcohol dehydrogenase. The inhibiting capacity of the compound for glycolic acid aromatic esters diamides increases depending on the position of two residua of glycolic acid: ortho < meta < para. A decrease in activity of the isoforms of rat liver aldehyde dehydrogenase does not exceed 40%. It is shown that glycolic acid ether amides are noncompetitive inhibitors, amides of aromatic esters in case of the substituent presence in the ortho- and para-positions are competitive or in the meta-position noncompetitive inhibitors. Linear correlation under the comparison of the inhibition constants with the corresponding parameters of hydrophobicity of butyl, 2-methylbutyl and 3-methylbutyl esters of glycolic acid have been found.

Alcohol Dehydrogenase↗
PubMed2000

Synthesis of 2-Oxo amide triacylglycerol analogues and study of their inhibition effect on pancreatic and gastric lipases.

A general method for the synthesis of chiral 2-oxo amide triacylglycerol analogues, from (R)- or (S)-3-aminopropane-1,2-diol, was developed. These novel inhibitors of digestive lipases are analogues of the triacylglycerol molecule, a natural substrate of lipases, and they were designed to contain the 2-oxo amide functionality in place of the scissile ester bond at the sn-1 or sn-3 position and nonhydrolysable ether bonds instead of ester bonds at the other two remaining positions. The 2-oxo amide derivatives synthesised were tested for their ability to form stable monomolecular films at the air/water interface by recording their surface pressure/molecular area compression isotherms. The inhibition of porcine pancreatic and human gastric lipases by the 2-oxo amides was studied by means of the monolayer technique with mixed films of 1,2-dicaprin and with variable proportions of each inhibitor. The alpha50 values of these triacylglycerol analogues for PPL and HGL varied between 4.4 to 7.0% and 5.6 to 15.9%, respectively. The chirality at the sn-2 position of 2-oxo amide triacylglycerol analogues affected the alpha50 value for HGL, but not for PPL.

Enzyme Inhibitors↗
PubMed2007

Kojic acid-tripeptide amide as a new tyrosinase inhibitor.

Twenty two kojic acid-tripeptide amides were prepared using a solid-phase Fmoc/tBu strategy with Rink Amide SURE(R) resin. To effectively obtain kojic acid-tripeptide amide conjugates, the coupling conditions of kojic acid to the tripeptide on the resin were optimized. The tyrosinase inhibitory activity of kojic acid-tripeptide amides and the effect of the amino acid sequence on the activity were compared with those of kojic acid-tripeptide acids. The stability of kojic acid-tripeptide amides were then compared with those of kojic acid and kojic acid-tripeptides acids. As a consequence, kojic acid-FWY-NH(2) proved to be the best compound, with the highest inhibitory activity, which was maintained over different storage times under various temperatures and pHs.

Drug Stability↗
PubMed2005

Vitamin E amides, a new class of vitamin E analogues with enhanced proapoptotic activity.

Vitamin E (VE) analogues, epitomized by alpha-tocopheryl succinate (alpha-TOS), are proapoptotic agents with selective antineoplastic activity. The molecule of alpha-TOS comprises several structurally and functionally distinct moieties that can be modified in order to yield analogues with higher activity. In order to find analogues with higher apoptogenic efficacy, we prepared novel compounds where the ester bond was replaced by an amide bond. All of these analogues were significantly more proapoptotic than their ester counterparts, with alpha-tocopheryl maleyl amide being the most effective. Importantly, methylation of the free carboxylic group completely obliterated apoptogenic activity of the compounds. Similarly as shown for the ester analogues, the amides induced apoptosis by mitochondrial destabilization. Superiority of amides over the ester analogues may be due to their higher partitioning into the lipid phase, as suggested by the log p-values that were lower for the amides than the corresponding esters. In conclusion, we present evidence that modification of the ester bond of agents such as alpha-TOS can be used as a basis for generating novel analogues with higher efficacy of killing malignant cells, an activity that suggests anticancer effect of the agents.

Apoptosis↗
PubMed1989

Molecular recognition in synthetic polymers. Enantiomeric resolution of amide derivatives of amino acids on molecularly imprinted polymers.

Molecular imprints were prepared using L-phenylalanine anilide as the print molecule and methacrylic acid as the functional monomer. Methacrylic acid interacts ionically with the primary amine of the print molecule and via hydrogen bonding with the amide function. In the HPLC mode such polymers were shown to exhibit efficient enantiomeric resolution of a racemic mixture of the original print molecule. Enantiomeric resolution was shown to be dependent on the ratio of methacrylic acid to print molecule in the pre-polymerization mixture and specific for the presence of both print molecule and functional monomer. Further analyses showed the importance of both the primary amino and amide functions in the correct stereochemistry for recognition and enantiomeric resolution of compounds on such polymers. Other amide derivatives of amino acids including p-nitroanilides, beta-naphthylamides and amides were recognized by such polymers, and enantiomeric resolution was obtained for amide derivatives of amino acid ranging from alanine to tryptophan on a single polymer. The implications of these findings with respect to the mechanism of recognition and the ability to predict enantiomeric resolution of molecules on molecularly imprinted polymers will be discussed.

Amino Acids↗
PubMed1998

Nitrilase catalyzes amide hydrolysis as well as nitrile hydrolysis.

While amides were reported to be completely inert as substrates for all nitrilases reported to date, the nitrilase from Rhodococcus rhodochrous J1, which catalyzes the hydrolytic cleavage of the C-N triple bond in nitrile to form acid and ammonium, was surprisingly found to catalyze hydrolysis of amide to acid and ammonium stoichiometrically. This nitrilase exhibited a Km of 2.94 mM for benzamide, similar to that for benzonitrile as the original substrate (2.10 mM), but the Vmax for benzamide was six orders of magnitude lower than that for benzonitrile. Benzamide inhibited the nitrilase reaction in a reversible, apparently competitive manner. A mutant nitrilase containing alanine or serine instead of Cys165, which is essential for nitrilase catalytic activity, showed no amidase activity. This observation demonstrated that Cys165 plays a crucial role in the hydrolysis of amides as well as nitriles. Together with some reports that certain nitrilases were previously noted to produce low amounts of amide as a by-product from nitrile, the above unexpected findings suggested the existence of a common tetrahedral intermediate in the nitrilase reaction involving nitrile or amide as a substrate.

Aminohydrolases↗