5-aminopentanoic Acid Research Articles

Limiting diffusion coefficients of [Formula: see text],[Formula: see text]-amino acids in water and in sodium chloride aqueous solutions at 298.15 K.

Transport properties of model compounds in aqueous solutions such as amino acids can provide valuable information in order to understand the complex interactions in aqueous solutions as well as the protein stability in water and the relevant factors involved. Informations about the diffusion of amino acids in water and in aqueous solutions of sodium chloride are very scarce, especially for the 5-aminopentanoic acid and 6-aminohexanoic acid. In this study, limiting binary mutual diffusion coefficients at 298.15 K of 5-aminopentanoic and 6-aminohexanoic acids in aqueous solutions of NaCl 0.15 mol kg-1, using the Taylor dispersion technique, were determined and the results compared with the limiting binary mutual diffusion coefficients for 2-aminopentanoic acid, and 2-aminohexanoic acid, obtained in the same experimental conditions. The discussion of the properties of the selected amino acids is centered on the positions of the ionic groups in the hydrocarbon chain and, in addition, we have discussed the effects of NaCl on their structures and properties. The data on diffusion properties are supported by 1H, 13C and 23Na NMR experiments, which we have obtained for 5-aminopentanoic and 6-aminohexanoic acids, in aqueous solution, also in the presence of NaCl.

POTENTIAL METABOLITES WITH DIAGNOSTIC VALUE IN PLASMA FOR ANGIOIMMUNOBLASTIC T‐CELL LYMPHOMA BY LC‐MS BASED UNTARGETED METABONOMICS STUDY

Background: Angioimmunoblastic T-cell lymphoma (AITL) is an uncommon subtype of mature peripheral T-cell lymphoma (PTCL). and its characteristics is not fully understood. Because it is a rare form of lymphoma, there is difficulty in diagnosis based on current traditional method. Metabolic reprogramming is a major cancer hallmark, which provides cancer cells with vital energy and metabolites. Mass spectrometry-based metabolomics has emerged as an informative technique for profiling metabolic features associated with cancers. Objective: This study aim to discover metabolites with potential diagnostic value in plasma of AITL patient. Methods: Plasma was collected from 27 patients newly diagnosed with AITL in Zhejiang Cancer Hospital and 30 age- and gender- matched healthy controls. An aliquot of 50 μL plama was added with 150 μL of chilled acetonitrile, vortexed and centrifuged. the supernatant was dried, reconstituted for metabolomics. Mass spectrometry analysis was performed on a UPLC coupled with a Q Exactive Orbitrap mass spectrometer. “XCMS” and “MetaX” were used to analyze LC-MS data. Significant features were selected as candidate for identification by matching their MS and MS/MS data with online databases HMDB and METLIN. Results: Eighteen altered metabolites (choline, betaine, L-leucine, creatine, 2-butyl-1H-benzimidazole, hypoxanthine, methionine sulfoximine, L-carnitine, 2-hydroxycinnamic acid, L-tyrosine, D-tryptophan, indoleacrylic acid, lysoPC(P-18:0), 5-aminopentanoic acid, uric acid, sucrose, L-lactic) were indentified (VIP value>1, p Conclusion: This study revealed metabolic reprogram and potential diagnostic metabolites in plasma for AITL, and gave more metabolic information for carcinogenesis of AITL. Disclosures No relevant conflicts of interest to declare.

Dynamic changes of postprandial plasma metabolites after intake of corn-soybean meal or casein-starch diets in growing pigs

BackgroundPostprandial nutrients utilization and metabolism of a certain diet is a complicated process. The metabolic feature of pigs after intake of corn-soybean meal or casein-starch diets are largely unknown. Therefore, this study was conducted to investigate the dynamic postprandial changes of plasma metabolic profile using growing pigs using metabolomics.MethodsTwenty-four growing pigs with average initial body weight (BW) about 30 kg were placed in metabolic cages and then fitted with precaval vein catheters. Pigs were fed daily 4% of initial body weight. Two experimental diets were included: (i) a starch-casein based purified diet (PD) and (ii) a common corn-soybean meal diet (CD). Plasma was collected before feeding and 0.5 h, 1 h, 2 h, 4 h, 8 h after feeding.ResultsIn both diets, compared to prior to feeding, the concentrations of glucose, most amino acids, metabolites such as 5-aminopentanoic acid, pipecolic acid, ornithine and 5-hydroxy-L-tryptophan were significantly increased in plasma during the first hour, whereas the concentrations of plasma triglycerides, glutamate, glycine, palmitelaidic acid, 13-HODE and oleic acid were decreased in the first hour. Compared with PD group, concentration of plasma leucine and isoleucine declined at 30 min in CD group. Plasma linoleic acid, sphingosine and many dipeptides were significantly higher in pigs fed CD.ConclusionMost significant metabolic changes occurred during the first hour after feeding and then became relatively stable after 2 h in both diets. These results show a broad scope picture of postprandial changes in plasma metabolites after intake of PD and CD and could be a reference for further nutrition intervention as well as the design of nutritional studies.

β-secretase 1 inhibitory activity and AMP-activated protein kinase activation of Callyspongia samarensis extracts

The methanolic extract of Callyspongia samarensis (MCS) significantly inhibited β-secretase 1 (IC50 99.82 µg/mL) in a dose-dependent manner and demonstrated a noncompetitive type of inhibition. Furthermore, it exhibited the highest AMPK activation (EC50 14.47 μg/mL) as compared with the standard, Aspirin (EC50 >100 μg/mL). HPLC/ESI-MS analysis of MCS extract revealed 15 peaks, in which nine peaks demonstrated similar fragmentation pattern with the known compounds in literature and in database library: 5-aminopentanoic acid (1), 4-aminobutanoic acid (3), Luotonin A (4), (E)-3-(1H-imidazol-5-yl) prop-2-enoic acid (8), Galactosphingosine (10), D-sphingosine (11), 5,7,4′-trihydroxy-3′,5′-dimethoxyflavone (12), hydroxydihydrovolide (13), and 3,5-dibromo-4-methoxyphenylpyruvic acid (14); and 6 peaks are not identified (2, 5–7, 9, and 15). Acute oral toxicity test of MCS extract revealed that it is nontoxic, with an LD50 of >2000 mg/kg. Assessment of BBB permeability of MCS extract showed that compound 15 was able to cross the BBB making it a suitable candidate for developing CNS drugs.

Partial Molar Volumes, Partial Molar Compressibilities, and Viscosities of α,ω-Amino Acids in Water and in Aqueous Solutions of Sodium Chloride over a Temperature Range of 293.2–333.2 K

Density, sound velocity, and viscosity were measured in the temperature range of 288.15–308.15 K at intervals of 5 K for glycine, 3-aminopropanoic acid, 4-aminobutanoic acid, 5-aminopentanoic acid,...

Synthesis and antiradical activity of novel copper(II) complexes of long chain reduced Schiff base ligands

Oxidative stress is the cause of many diseases and at the heart of it is the overproduction of reactive oxygen species (ROS). There are several protective enzymes, e.g., superoxide dismutases (SOD), able to decrease the level of ROS in the cell; however, a therapeutic use of these enzymes is problematic. Small molecule compounds and complexes able to scavenge free radicals such as superoxide anion radicals could be used instead. These compounds are often called SOD-mimics and various researches are interested in synthesis and study of these compounds. In our study, a series of Cu(II) complexes were synthesized, containing reduced Schiff base ligands prepared from salicylaldehyde and amino acids with longer chain length (5-aminopentanoic acid, 6-aminohexanoic acid, 8-aminooctanoic acid, 11-aminoundecanoic acid, and 12-aminododecanoic acid). Complexes prepared from these ligands are novel and were prepared using three different methods. An assay based on the ability to inhibit reduction of iodonitrotetrazolium dye by superoxide anion radicals was used to determine antiradical activity of the prepared complex. Most of the prepared complexes proved to be good antiradical agents compared to cystamine and the copper(II) complex with Schiff base type ligand N-salicylidene-β-alanine. The best IC50 values of the radical transfer of the prepared compounds were two complexes of N-(2-hydroxybenzyl)-11-aminoundecanoic acid: 97.0 ± 1.9 and 45.1 ± 0.5 μM.

Biosynthesis of Long-Chain N-Acyl Amide by a Truncated Polyketide Synthase-Nonribosomal Peptide Synthetase Hybrid Megasynthase in Fungi.

Truncated iterative polyketide synthase-nonribosomal peptide synthetase (PKS-NRPS) megasynthases in which only the C domain is present are widespread in fungi, yet nearly all members have unknown functions. Bioinformatics analysis showed that the C domains of such PKS-C enzymes are noncanonical due to substitution at the second histidine in the active site HHxxxDG motif. Here, we used genome mining strategy to characterize a cryptic PKS-C hybrid from Talaromyces wortmanii and discovered the products are reduced long-chain polyketides amidated with a specific ω-amino acid 5-aminopentanoic acid (5PA). The wortmanamides resemble long-chain N-acyl-amide signaling lipids that target diverse receptors including GPCRs. The noncanonical C domain of this PKS-C hybrid was also demonstrated to be a bona fide condensation domain that specifically selects 5PA and catalyzes amidation to release polyketide chain.

Variation of the Molecular Conformation, Shape, and Cavity Size in Dinuclear Metalla-Macrocycles Containing Hetero-Ditopic Dithiocarbamate-Carboxylate Ligands from a Homologous Series of N-Substituted Amino Acids.

A homologous series of dithiocarbamate ligands derived from N-substituted amino acids was reacted with different diorganotin dichlorides to give 18 diorganotin complexes. Spectroscopic and mass spectrometric analysis evidenced the formation of assemblies with six-coordinate tin atoms embedded in skewed-trapezoidal bipyramidal coordination environments of composition C2SnS2O2. Single-crystal X-ray diffraction analysis for three of the compounds revealed a one-dimensional polymeric structure for the complex with the ligand derived from 5-aminopentanoic acid, which through further intermolecular Sn···O interactions generated an overall two-dimensional coordination polymer containing 40-membered hexanuclear tin macrocycles. On the contrary, the ligands derived from 6-aminohexanoic and 8-aminooctanoic acid provided the expected 22- and 26-membered dinuclear macrocyclic structures. Density functional theory calculations for a representative series of macrocyclic complexes of composition [Me2SnLx]2 with Lx = ¯S2CN(Me)-(CH2)x-COO¯ (x = 3-12) enabled a detailed analysis of the variations in the molecular conformation, shape, and cavity size of the macrocycles in dependence of the aliphatic spacer. Because of odd-even effects, the difunctional ligands can adopt either a curved or a twisted-pincer shape, while the SnSxO4-x (x = 0-4) moieties can act either as linear or angular tectons with varying connectivity angles.

Effect of temperature on the surface properties of α,ω-amino acids in dilute aqueous solutions

In this work, experimental results for surface tension of aqueous solutions of 3-aminopropanoic acid, 4-aminobutanoic acid, 5-aminopentanoic acid and 6-aminohexanoic acid at T = (293.15, 298.15, 303.15 and 308.15) K at several concentrations are presented. The results were used to evaluate the limiting experimental slopes of surface tension with respect to mole fraction at each temperature. Surface tension measurements were taken using a LAUDA TVT-2 drop volume tensiometer with temperature control better than 0.1 K at T = (293.15, 298.15, 303.15 and 308.15) K The thermodynamic behavior of the aqueous α,ω-amino acid solutions is compared with that reported for α-amino acids in water. The surface behavior is discussed in terms of the effect of the hydrocarbon chain and the position of polar groups on water structure. The temperature dependence of the limiting slopes of surface tension with respect to mole fraction, derived from surface tension measurements, is discussed.

Factors affecting the pharmacokinetics and pharmacodynamics of PEGylated liposomal irinotecan (IHL-305) in patients with advanced solid tumors.

IHL-305 is a PEGylated liposomal formulation of irinotecan (CPT-11). The objective of this study was to evaluate the factors associated with interpatient variability in the pharmacokinetics and pharmacodynamics of IHL-305 in patients with advanced solid tumors. IHL-305 was administered intravenously once every 4 weeks as part of a Phase I study. Pharmacokinetic studies of the liposomal sum total CPT-11, released CPT-11, SN-38, SN-38G, 7-ethyl-10-[4-N-(5-aminopentanoic acid)-1-piperidino]-carbonyloxycamptothecin, and 7-ethyl-10-[4-amino-1-piperidino]-carbonyloxycamptothecin in plasma were performed. Noncompartmental and compartmental pharmacokinetic analyses were conducted using pharmacokinetic data for sum total CPT-11. The pharmacokinetic variability of IHL-305 is associated with linear and nonlinear clearance. Patients whose age and body composition (ratio of total body weight to ideal body weight [TBW/IBW]) were greater than the median age and TBW/IBW of the study had a 1.7-fold to 2.6-fold higher ratio of released CPT-11 area under the concentration versus time curve (AUC) to sum total CPT-11 AUC. Patients aged <60 years had a 1.3-fold higher ratio of percent decrease in monocytes at nadir to percent decrease in absolute neutrophil count at nadir as compared with patients aged ≥60 years. There was an inverse relationship between patient age and percent decrease in monocytes at nadir, ie, younger patients have a higher percent decrease in monocytes. Patients with a higher percent decrease in monocytes at nadir have a decreased plasma exposure of sum total CPT-11. The pharmacokinetics and pharmacodynamics of IHL-305 are consistent with those of other PEGylated liposomal carriers. Interpatient variability in the pharmacokinetics and pharmacodynamics of IHL-305 was associated with age, body composition, and monocytes.

Synthesis and characterization of higher amino acid Schiff bases, as monosodium salts and neutral forms. Investigation of the intramolecular hydrogen bonding in all Schiff bases, antibacterial and antifungal activities of neutral forms

Schiff bases derived from 5-nitro-salicylaldehyde and 4-aminobutyric acid, 5-aminopentanoic acid and 6-aminohexanoic acid were synthesized both as monosodium salts (1a–3a) and neutral forms (1b–3b). The monosodium-Schiff bases were characterized by elemental analysis, 1H/13C NMR, IR, powder XRD, UV–vis spectra and conductivity measurements. The neutral-Schiff bases were characterized by elemental analysis, 1H/13C NMR, 2D NMR (HMQC), mass, IR, powder XRD, UV–vis spectra and conductivity measurements. The intramolecular hydrogen bonding and related tautomeric equilibria in all the Schiff bases were studied by UV–vis and 1H NMR spectra in solution. Additionally, the neutral-Schiff bases were screened against Staphylococcus aureus-EB18, S. aureus-ATCC 25923, Escherichia coli-ATCC 11230, Candida albicans-M3 and C. albicans-ATCC 16231.

Osmotic and activity coefficients of α,ω-amino acids in aqueous solutions at 298.15 K

The osmotic coefficients of aqueous solutions of the α,ω-amino acids: 3-aminopropanoic acid, 4-aminobutanoic acid, 5-aminopentanoic acid and 6-aminohexanoic acid were measured using the isopiestic method at 298.15K. The activity coefficients of these solutes were calculated from the experimental osmotic coefficients and the pairwise free energy coefficients for solute–solute interactions were obtained using the Mc-Millan-Mayer theory. The results are compared with the activity coefficients of α-amino acids and are discussed in terms of solute–solute interactions.

Binary Diffusion Coefficients of Aqueous Straight-Chain Amino Acids at Infinitesimal Concentration and Temperatures from (298.2 to 333.2) K

Mutual diffusion coefficients for aqueous solutions of 3-aminopropanoic acid (β-alanine), 4-aminobutanoic acid (γ-aminobutyric acid), 5-aminopentanoic acid, 6-aminohexanoic acid, and 7-aminoheptanoic acid at infinitesimal concentration were measured at atmospheric pressure and temperatures from (298.2 to 333.2) K using the Taylor dispersion method. The results were compared with those of the structural isomers measured in our previous studies to examine the effect of position of amino and carboxylic acid groups on the values of diffusion coefficients. The diffusion coefficients of all amino acid isomers were almost the same, indicating that the diffusion coefficients of amino acids measured in our studies were mostly determined by the molar mass and the increase in the distance between amino and carboxylic acid groups was not an important factor. The temperature dependences of the diffusion coefficients were well-correlated with viscosity of water, η, as D12/T = αηβ where D12 is the diffusion coefficient ...

Corrosion Inhibition Properties of Triazine Derivatives Containing Carboxylic Acid and Amine Groups in 1.0 M HCl Solution

In the present work, the corrosion inhibition properties of three amino acid compounds, glycine (Gly), 2,2′-azanediyldiacetic acid (IDA), 5-aminopentanoic acid (5-APA), and two triazine (Tris) derivatives containing Gly or IDA units were investigated. It was found that the amino acids and their triazine derivatives behaved like mixed-type corrosion inhibitors that reduced oxidative dissolution and retarded a hydrogen emission reaction. In the case of the three amino acids, it was found that the increase in the length and the number carboxylic acid groups of the molecules enhanced the corrosion inhibition properties. It was also observed that the presence of triazine ring enhanced the corrosion inhibition properties significantly. It was suggested that the adsorption of triazine derivatives on a metal surface was the Langmuir isotherm adsorption and mainly physisorption. In the case of Tris-IDA, the six acetic acid moieties emanating from the triazine ring led to partial negative charges on the outer layer...

Effect of Temperature on The Solubility of α-Amino Acids and α,ω-Amino Acids in Water

The aqueous solubilities of glycine, dl-α-alanine (2-aminopropanoic acid), dl-α-aminobutyric acid (2-aminobutanoic acid), dl-α-norvaline (2-aminopentanoic acid), dl-α-norleucine (2-aminohexanoic acid), β-alanine (3-aminopropanoic acid), γ-aminobutyric acid (4-aminobutanoic acid), 5-aminovaleric acid (5-aminopentanoic acid), and 6-aminocaproic acid (6-aminohexanoic acid) were determined from 293.15 to 323.15 K at intervals of 5.00 K using the gravimetric method. The temperature dependence of the solubility of α-amino acids and α,ω-amino acids in water is well described by the van’t Hoff equation. Linear van’t Hoff plots were used to determine the differential enthalpy of solution. The results obtained are compared with reported values in literature and are discussed in terms of the position of the ionic groups in the hydrocarbon chain.

Effect of temperature on the dilution enthalpies of α,ω-amino acids in aqueous solutions

Abstract Dilution enthalpies of aqueous solutions of 3-amino propanoic acid, 4-amino butanoic acid, 5-amino pentanoic acid, and 6-amino hexanoic acid were determined at T = (293.15, 298.15, 303.15, and 308.15) K using an LKB flow microcalorimeter. The homotactic interaction coefficients were obtained according to the McMillan–Mayer theory from the experimental data. For all the systems studied, the dilution of α,ω-amino acids in water is an exothermic process; the pair coefficients have positive values which increases with chain length. The obtained values of the interaction coefficients are interpreted in terms of solute–solvent and solute–solute interactions and are used as indicative of hydrophobic behavior of the amino acid studied.

Effect of omeprazole on the pharmacokinetics and toxicities of irinotecan in cancer patients: A prospective cross-over drug–drug interaction study

BackgroundOmeprazole is one of the most prescribed medications worldwide and within the class of proton pump inhibitors, it is most frequently associated with drug interactions. In vitro studies have shown that omeprazole can alter the function of metabolic enzymes and transporters that are involved in the metabolism of irinotecan, such as uridine diphosphate glucuronosyltransferase subfamily 1A1 (UGT1A1), cytochrome P-450 enzymes subfamily 3A (CYP3A) and ATP-binding cassette drug-transporter G2 (ABCG2). In this open-label cross-over study we investigated the effects of omeprazole on the pharmacokinetics and toxicities of irinotecan. MethodsFourteen patients were treated with single agent irinotecan (600mg i.v., 90min) followed 3weeks later by a second cycle with concurrent use of omeprazole 40mg once daily, which was started 2weeks prior to the second cycle. Plasma samples were obtained up to 55h after infusion and analysed for irinotecan and its metabolites 7-ethyl-10-hydroxycampothecin (SN-38), SN-38-glucuronide (SN-38G), 7-ethyl-10-[4-(1-piperidino)-1-amino]-carbonyloxycamptothecin (NPC) and 7-ethyl-10-[4-N-(5-aminopentanoic acid)-1-piperidino]-carbonyloxycamptothecin (APC) by high-performance liquid chromatography (HPLC). Non-compartmental modelling was performed. Toxicities were monitored during both cycles. Paired statistical tests were performed with SPSS. ResultsThe exposure to irinotecan and its metabolites was not significantly different between both cycles. Neither were there significant differences in the absolute nadir and percentage decrease of WBC and ANC, nor on the incidence and severity of neutropenia, febrile neutropenia, diarrhoea, nausea and vomiting when irinotecan was combined with omeprazole. ConclusionOmeprazole 40mg did not alter the pharmacokinetics and toxicities of irinotecan. This widely used drug can, therefore, be safely administered during a 3-weekly single agent irinotecan schedule.

Effect of Temperature on the Volumetric Properties of α,ω-Amino Acids in Dilute Aqueous Solutions

The partial molar volume at infinite dilution of aqueous solutions of 3-aminopropanoic acid, 4-aminobutanoic acid, 5-aminopentanoic acid and 6-aminohexanoic acid were determined at T=(293.15,298.15,303.15 and 308.15 K) from density measurements. The thermodynamic behavior of the aqueous α,ω-amino acid solutions is compared with that reported for α-amino acids in water. The interaction volume is calculated and the influence of charged and uncharged groups of the amino acids is discussed in terms of solute–solvent interactions.

Impaired irinotecan biotransformation in hepatic microsomal fractions from patients with chronic liver disease

The anticancer agent irinotecan is a prodrug that is hydrolyzed by hepatic carboxylesterase to its active and toxic metabolite SN-38 and oxidized by CYP3A4 to its inactive metabolite APC. Irinotecan therapy is complicated by co-administered drugs that inhibit CYP3A4 and decrease APC formation and that indirectly increase SN-38 formation. Dose adjustment in cancer patients with liver disease has been recommended. In microsomal fractions from patients with severe hepatic dysfunction both APC and SN-38 formation were decreased due to down-regulation of CYP3A4 and carboxylesterase enzymes. Thus relative SN-38 : APC formation was preserved. In some fractions the SN-38:APC ratio was increased, thus providing a possible explanation for clinical reports of increased SN-38 exposure in some patients with liver dysfunction. Close monitoring of SN-38 formation in patients with severe liver disease is warranted. Dose modification with the anticancer agent irinotecan is recommended in patients with severe liver dysfunction. This study evaluated the impact of liver disease on the relative formation of phase I products of irinotecan biotransformation in human microsomes in vitro. Microsomes from subjects with normal liver function and liver dysfunction (n=20) were assessed for irinotecan biotransformation and the expression of cytochrome P450 (CYP) 3A4 and carboxylesterase (CES) enzymes. Liver disease down-regulated CYP3A4 expression (median 33% of control, range 0-126%, P<0.05) and impaired CYP3A4-dependent oxidation of irinotecan to the inactive 7-ethyl-10-[4-N-(5-aminopentanoic acid)-1-piperidino]carbonyloxycamptothecin (APC) (median 0.2, range 0-1.21 pmol mg protein(-1) min(-1) compared with median 0.66, range 0-2.35 in control, P<0.01). CES-mediated hydrolysis of irinotecan to 7-ethyl-10-hydroxycamptothecin (SN-38) was also impaired in liver disease (median 8.38, range 0-20.7 pmol mg protein(-1) min(-1) compared with median 13.3, range 0-28.9 in control, P<0.05). In seven of 20 liver disease microsomes neither metabolite was detected but in three the SN-38:APC ratio was high (41-68) compared with the remaining 10 samples (ratio 11-36). Down-regulation of CYP3A4 in liver disease decreased APC formation from irinotecan. SN-38 production was decreased and CES1 and 2 were down-regulated in most samples. However, in a subset of disease samples SN-38 production was relatively high because CYP3A4 activity was markedly impaired. This may account for clinical reports of increased SN-38 exposure in some patients with liver disease. Dose adjustments in cancer patients with liver disease who receive irinotecan are important and circulating SN-38 concentrations should be monitored closely.

Enthalpies of formation of β-alanine, sarcosine, and 4-aminobutanoic acid from quantum chemical calculations

The standard molar enthalpies of formation of β-alanine, sarcosine, and 4-aminobutanoic acid in the gaseous phase at T = 298.15 K were calculated by the high-level Gaussian-4 method. The agreement with available experimental data is good for β-alanine and 4-aminobutanoic acid, while a significant discrepancy between theoretical and experimental enthalpy of formation values for sarcosine suggests the inaccuracy of experimental data for this compound. These results were also supported by isodesmic reaction calculations. The recommended values of Δ f H m ∘ (β-alanine, g, 298.15 K) = (−419.7 ± 4.0) kJ · mol −1, Δ f H m ∘ (sarcosine, g, 298.15 K) = (−389.0 ± 4.0) kJ · mol −1, and Δ f H m ∘ (4-aminobutanoic acid, g, 298.15 K) = (−436.7 ± 5.0) kJ · mol −1 together with those obtained earlier for glycine and alanine, enable one to determine the group additivity values (GAVs) for some groups with nitrogen bound to carbon. These GAVs were used to estimate the enthalpies of formation of 5-aminopentanoic acid, 6-aminohexanoic acid, and 8-aminooctanoic acid. For the two first species, the experimental and calculated values agree well. A large deviation observed for 8-aminooctanoic acid suggests that experimental Δ f H m ∘ ( cr ) value for this compound is not reliable.