Short-chain Aldehydes Research Articles

A Catalase-related Hemoprotein in Coral Is Specialized for Synthesis of Short-chain Aldehydes: DISCOVERY OF P450-TYPE HYDROPEROXIDE LYASE ACTIVITY IN A CATALASE

In corals a catalase-lipoxygenase fusion protein transforms arachidonic acid to the allene oxide 8R,9-epoxy-5,9,11,14-eicosatetraenoic acid from which arise cyclopentenones such as the prostanoid-related clavulones. Recently we cloned two catalase-lipoxygenase fusion protein genes (a and b) from the coral Capnella imbricata, form a being an allene oxide synthase and form b giving uncharacterized polar products (Lõhelaid, H., Teder, T., Tõldsepp, K., Ekins, M., and Samel, N. (2014) PloS ONE 9, e89215). Here, using HPLC-UV, LC-MS, and NMR methods, we identify a novel activity of fusion protein b, establishing its role in cleaving the lipoxygenase product 8R-hydroperoxy-eicosatetraenoic acid into the short-chain aldehydes (5Z)-8-oxo-octenoic acid and (3Z,6Z)-dodecadienal; these primary products readily isomerize in an aqueous medium to the corresponding 6E- and 2E,6Z derivatives. This type of enzymatic cleavage, splitting the carbon chain within the conjugated diene of the hydroperoxide substrate, is known only in plant cytochrome P450 hydroperoxide lyases. In mechanistic studies using (18)O-labeled substrate and incubations in H2(18)O, we established synthesis of the C8-oxo acid and C12 aldehyde with the retention of the hydroperoxy oxygens, consistent with synthesis of a short-lived hemiacetal intermediate that breaks down spontaneously into the two aldehydes. Taken together with our initial studies indicating differing gene regulation of the allene oxide synthase and the newly identified catalase-related hydroperoxide lyase and given the role of aldehydes in plant defense, this work uncovers a potential pathway in coral stress signaling and a novel enzymatic activity in the animal kingdom.

Toxicity of polyunsaturated aldehydes of diatoms to Indo-Pacific bioindicator organism Echinometra mathaei

Although it is well known suitability of early developmental stages of sea urchin as recommended model for pollutant toxicity testing, little is known about the sensitivity of Indo-Pacific species Echinometra mathaei to polyunsaturated aldehydes. In this study, the effect of three short chain aldehydes, 2,4-decadienal (DD), 2,4-octadienal (OD) and 2,4-heptadienal (HD), normally found in many diatoms, such as Skeletonema costatum, Skeletonema marinoi and Thalassiosira rotula, was evaluated on larval development of E. mathaei embryos. Aldehydes affected larval development in a dose-dependent manner, in particular HD>OD>DD; the results of this study highlighted the higher sensitivity of this species toward aldehydes compared with data registered for other sea urchin species. In comparison with studies reported in the literature, contrasting results were observed during our tests; therefore, an increasing toxic effect was registered with decreasing the chain length of aldehydes. This work could provide new insights in the development of new toxicological assays toward most sensitive species.

A novel ultrasound-assisted back extraction reverse micelles method coupled with gas chromatography–flame ionization detection for determination of aldehydes in heated edibles oils

A novel ultrasound-assisted back extraction reverse micelles coupled with gas chromatography–flame ionization detection has been developed for the extraction and determination of some short chain aldehydes in different heated edible oil samples. After the homogenization of the oil samples with Triton X-100, 200μL of methanol was added to facilitate the phase separation. The aqueous micelle phase has been separated by centrifugation, then it was treated with a mixture of H2O: CHCl3 and ultrasonic vibration, were used to effectively back-extraction of the analytes into the chloroform phase. The sedimented organic phase was obtained after centrifugation, withdrawn into the microsyringe and directly injected into the GC–FID system. The calibration graphs were linear in the range 0.05–20mgL−1. The limits of detection were in the range of 0.02–0.15mgL−1. This procedure was successfully applied for determination of propanal, butanal, hexanal and heptanal in real heated oil samples.

Haloferax volcanii, as a Novel Tool for Producing Mammalian Olfactory Receptors Embedded in Archaeal Lipid Bilayer.

The aim of this study was to explore the possibility of using an archaeal microorganism as a host system for expressing mammalian olfactory receptors (ORs). We have selected the archaeon Haloferax volcanii as a cell host system and one of the most extensively investigated OR, namely I7-OR, whose preferred ligands are short-chain aldehydes, such as octanal, heptanal, nonanal. A novel plasmid has been constructed to express the rat I7-OR, fused with a hexahistidine-tag for protein immunodetection. The presence of the recombinant receptor at a membrane level was demonstrated by immunoblot of the membranes isolated from the transgenic archaeal strain. In addition, the lipid composition of archaeonanosomes containing ORs has been characterized in detail by High-Performance Thin-Layer Chromatography (HPTLC) in combination with Matrix-Assisted Laser Desorption Ionization—Time-Of-Flight/Mass Spectrometry (MALDI-TOF/MS) analysis.

Identification of human semiochemicals attractive to the major vectors of onchocerciasis.

BackgroundEntomological indicators are considered key metrics to document the interruption of transmission of Onchocerca volvulus, the etiological agent of human onchocerciasis. Human landing collection is the standard employed for collection of the vectors for this parasite. Recent studies reported the development of traps that have the potential for replacing humans for surveillance of O. volvulus in the vector population. However, the key chemical components of human odor that are attractive to vector black flies have not been identified.Methodology/Principal FindingsHuman sweat compounds were analyzed using GC-MS analysis and compounds common to three individuals identified. These common compounds, with others previously identified as attractive to other hematophagous arthropods were evaluated for their ability to stimulate and attract the major onchocerciasis vectors in Africa (Simulium damnosum sensu lato) and Latin America (Simulium ochraceum s. l.) using electroantennography and a Y tube binary choice assay. Medium chain length carboxylic acids and aldehydes were neurostimulatory for S. damnosum s.l. while S. ochraceum s.l. was stimulated by short chain aliphatic alcohols and aldehydes. Both species were attracted to ammonium bicarbonate and acetophenone. The compounds were shown to be attractive to the relevant vector species in field studies, when incorporated into a formulation that permitted a continuous release of the compound over time and used in concert with previously developed trap platforms.Conclusions/SignificanceThe identification of compounds attractive to the major vectors of O. volvulus will permit the development of optimized traps. Such traps may replace the use of human vector collectors for monitoring the effectiveness of onchocerciasis elimination programs and could find use as a contributing component in an integrated vector control/drug program aimed at eliminating river blindness in Africa.

Chitosan Liposomal microspheres for Ricinoleic acid Encapsulation

Ricinoleic acid (RA) is a C18 fatty acid (FA) with a double bond at the C 9 position and a hydroxyl group at the C(12) position (cis-12-hydroxyoctadeca-9-enoic acid). Recently, RA has been reported as a pro/anti-inflammatory and analgesic agent for topical applications to be considered as an alternative to irritant substances that relive pain. However, RA when it is exposed to air, it reacts with the oxygen and decomposes into short-chain aldehydes and ketones. Moreover, pathologically, small amount of anaesthetic agent acts on peripheral nerves, producing reversible block in transmission of peripheral nerves impulses. However, larger amounts effect potentially in the central nervous system and may cause cardiac arrest. Accordingly, extended release formulations for local anaesthetic agent such as encapsulation, are highly demanded if the drug will be used for long period. In this work, ricinoleic acid, extracted and characterized, was encapsulated into a new matrix made of phospholipid liposomes and chitosan to protect and control RA release. RA release was controlled by crosslinking the matrices using glutaraldehyde. Spectral and morphology analysis are used to characterize the produced microshpers. The cytotoxicity test is considered to examine the final product biocompatibility. The encapsulation efficiency was investigated by UV- Visible spectroscopy.

Chemical compositions of the volatile extracts from seeds of Dendranthema nankingense and Borago officinalis

Volatile extracts from the seeds of Dendranthema nankingense Hand.-Mazz. and Borago officinalis L. were prepared using simultaneous distillation and extraction, and analyzed with gas chromatography–mass spectrometry on two capillary gas chromatography columns of different polarity. Ninety-five volatile compounds were identified in D. nankingense seeds, with hexanal, benzeneacetaldehyde, borneol, (−)-camphor, and 3-methyl-1-butanol being the predominant species. Sixty-five volatile compounds were identified in B. officinalis seeds, with 2-pentanone, 2,3-dihydro-benzofuran, 3-methyl butanal, and hexanal being the most abundant species. Thirty-three compounds, including short-chain aliphatic aldehydes, alcohols, and ketones, were common to both seeds. The volatile composition of both seeds varied significantly depending on their respective origins. The volatile terpenoids borneol and (−)-camphor could be key bioactive contributors to the characteristic flavor and cooling effects of D. nankingense. For the first time, coumaran was identified as an abundant species in plant seeds.

Screening of volatile compounds composition of white truffle during storage by GCxGC-(FID/MS) and gas sensor array analyses

White truffle (Tuber magnatum Pico) is one of the most valuable delicacies of the Italian and French cuisine. Previous works on truffle aroma report sulfur compounds and short-chain aldehydes as typical constituents which abundance is influenced by storage conditions. In this study, the head space of truffle aroma has been evaluated by two different (innovative) approaches: HS-SPME extraction and comprehensive two-dimensional gas chromatography (GCxGC), exploiting a dual-stage loop-type modulator within a GC system with simultaneous FID and MS double detection, analysis and Gas sensors array system analysis. Gas chromatographic peak identification was carried out by means of dedicated laboratory-made GC–MS libraries and comparison of Retention Indices with those retrieved from literature, while peak quantification by means of a specifically designed software for comprehensive GC. The truffle samples were stored at +8 °C for four days in three different ways: wrapped in blotting paper or covered by rice or under vacuum. Eighty compounds were identified with high confidence (>90% of mass spectra similarity). PCA of compounds relative percentages showed differences among the fresh product and truffles stored in rice and under vacuum; on the contrary no significant volatiles composition modification was observed for truffles stored in paper.

Molecular mechanisms of aldehyde toxicity: a chemical perspective.

Aldehydes are electrophilic compounds to which humans are pervasively exposed. Despite a significant health risk due to exposure, the mechanisms of aldehyde toxicity are poorly understood. This ambiguity is likely due to the structural diversity of aldehyde derivatives and corresponding differences in chemical reactions and biological targets. To gain mechanistic insight, we have used parameters based on the hard and soft, acids and bases (HSAB) theory to profile the different aldehyde subclasses with respect to electronic character (softness, hardness), electrophilic reactivity (electrophilic index), and biological nucleophilic targets. Our analyses indicate that short chain aldehydes and longer chain saturated alkanals are hard electrophiles that cause toxicity by forming adducts with hard biological nucleophiles, e.g., primary nitrogen groups on lysine residues. In contrast, α,β-unsaturated carbonyl derivatives, alkenals, and the α-oxoaldehydes are soft electrophiles that preferentially react with soft nucleophilic thiolate groups on cysteine residues. The aldehydes can therefore be grouped into subclasses according to common electronic characteristics (softness/hardness) and molecular mechanisms of toxicity. As we will discuss, the toxic potencies of these subgroups are generally related to corresponding electrophilicities. For some aldehydes, however, predictions of toxicity based on electrophilicity are less accurate due to inherent physicochemical variables that limit target accessibility, e.g., steric hindrance and solubility. The unsaturated aldehydes are also members of the conjugated type-2 alkene chemical class that includes α,β-unsaturated amide, ketone, and ester derivatives. Type-2 alkenes are electrophiles of varying softness and electrophilicity that share a common mechanism of toxicity. Therefore, exposure to an environmental mixture of unsaturated carbonyl derivatives could cause “type-2 alkene toxicity” through additive interactions. Finally, we propose that environmentally derived aldehydes can accelerate diseases by interacting with endogenous aldehydes generated during oxidative stress. This review provides a basis for understanding aldehyde mechanisms and environmental toxicity through the context of electronic structure, electrophilicity, and nucleophile target selectivity.

Effect of roasting on the volatile constituents of Trichosanthes kirilowii seeds

Roasted Trichosanthes kirilowii seeds have much more intense flavor than the raw seeds, and are commonly used as food and in the preparations of many medicinal formulations. Volatile constituents in the raw and roasted T. kirilowii seeds were separated by simultaneous distillation and extraction, and analyzed by gas chromatography–mass spectrometry on two capillary gas chromatography columns of different polarities (DB-WAX and HP-1). A total of 40 volatile compounds were identified in the raw seeds, with pentanal, 2-pentanol, styrene, (Z)-2-heptenal, (+)-calarene, and α-muurolene being the predominant compounds; 40 volatile compounds were also identified in the roasted seeds, with 3-methylbutanal, ethanol, 2-butanol, 2,3-butanediol, (E,E)-2,4-nonadienal, and 2-isopropyl-5-methyl-9-methylene-bicyclo[4.4.0]dec-1-ene being the most abundant compounds. A total of 15 compounds, mostly aldehydes, were common in both seeds. Roasting of T. kirilowii seeds resulted in a significant decrease in the levels of sesquiterpenes and short-chain aliphatic aldehydes. By contrast, high concentrations of 3-methylbutanal, ethanol, 2-butanol, and alkyl pyrazines were generated, which was responsible for the unique flavor of the roasted seeds. The study results may be useful for optimizing the roasting process and oil processing of T. kirilowii seeds.

CHEMICAL EFFECTS OF THE INCOMPLETE-OXIDATION PRODUCTS IN RESIDUAL GAS ON THE GASOLINE HCCI AUTO-IGNITION

Homogeneous charge compression ignition (HCCI) achieved by negative valve overlap (NVO) strategy can realize ignition phasing control through retaining residual gas. Except for the heating and dilution effects of residual gas, the presence of incomplete-oxidation products in residual gas also affects auto-ignition significantly. In order to investigate the compositions of incomplete-oxidation products, a fast instantaneous in-cylinder sampling system was developed. The in-cylinder sample gas was extracted just before the low temperature reaction and analyzed online quantitatively. It was found that the main incomplete-oxidation products in residual gas, which possibly have significant effects on auto-ignition, are short-chain hydrocarbons, aldehydes, and alcohols. Simulation analysis with a detailed chemical kinetic mechanism of gasoline surrogate was used to decouple the effects of these species. It indicated that CH2O, C2H4, and C2H2 play the most important roles in advancing auto-ignition. Also, the accumulation mechanisms of these main active species prior to auto-ignition are analyzed.

Emission of air pollutants from burning candles with different composition in indoor environments

Candle composition is expected to influence the air pollutants emissions, possibly leading to important differences in the emissions of volatile organic compounds and polycyclic aromatic hydrocarbons. In this regard, the purity of the raw materials and additives used can play a key role. Consequently, in this work emission factors for some polycyclic aromatic hydrocarbons, aromatic species, short-chain aldehydes and particulate matter have been determined for container candles constituted by different paraffin waxes burning in a test chamber. It has been found that wax quality strongly influences the air pollutant emissions. These results could be used, at least at a first glance, to foresee the expected pollutant concentration in a given indoor environment with respect to health safety standards, while the test chamber used for performing the reported results could be useful to estimate the emission factors of any other candle in an easy-to-build standardised environment.

Group III alcohol dehydrogenase from Pectobacterium atrosepticum: insights into enzymatic activity and organization of the metal ion-containing region

NAD(P)(+)-dependent alcohol dehydrogenases (ADH) are widely distributed in all phyla. These proteins can be assigned to three nonhomologous groups of isozymes, with group III being highly diverse with regards to catalytic activity and primary structure. Members of group III ADHs share a conserved stretch of amino acid residues important for cofactor binding and metal ion coordination, while sequence identities for complete proteins are highly diverse (<20 to >90%). A putative group III ADH PaYqhD has been identified in BLAST analysis from the plant pathogenic enterobacterium Pectobacterium atrosepticum. The PaYqhD gene was expressed in the heterologous host Escherichia coli, and the recombinant protein was purified in a two-step purification procedure to homogeneity indicating an obligate dimerization of monomers. Four conserved amino acid residues involved in metal ion coordination were substituted with alanine, and their importance for catalytic activity was confirmed by circular dichroism spectrum determination, in vitro, and growth experiments. PaYqhD exhibits optimal activity at 40°C with short carbon chain aldehyde compounds and NADPH as cofactor indicating the enzyme to be an aldehyde reductase. No oxidative activities towards alcoholic compounds were detectable. EDTA completely inhibited catalytic activity and was fully restored by the addition of Co(2+). Activity measurements together with sequence alignments and structure analysis confirmed that PaYqhD belongs to the butanol dehydrogenase-like enzymes within group III of ADHs.

2-Hydrazinoquinoline as a Derivatization Agent for LC-MS-Based Metabolomic Investigation of Diabetic Ketoacidosis.

Short-chain carboxylic acids, aldehydes and ketones are products and regulators of many important metabolic pathways. Their levels in biofluids and tissues reflect the status of specific metabolic reactions, the homeostasis of the whole metabolic system and the wellbeing of a biological entity. In this study, the use of 2-hydrazinoquinoline (HQ) as a novel derivatization agent was explored and optimized for simultaneous liquid chromatography-mass spectrometry (LC-MS) analysis of carboxylic acids, aldehydes and ketones in biological samples. The formation of carboxylic acid derivative is attributed to the esterification reaction between HQ and a carboxyl group, while the production of aldehyde and ketone derivatives is through the formation of Schiff bases between HQ and a carbonyl group. The compatibility of HQ with biological samples was demonstrated by derivatizing urine, serum and liver extract samples. Using this HQ-based approach, the kinetics of type 1 diabetes-induced metabolic changes was characterized by the LC-MS-based metabolomic analysis of urine samples from streptozotocin (STZ)-treated mice. Subsequently, carboxylic acid, aldehyde and ketone metabolites associated with STZ-elicited disruption of nutrient and energy metabolism were conveniently identified and elucidated. Overall, HQ derivatization of carboxylic acids, aldehydes and ketones could serve as a useful tool for the LC-MS-based metabolomic investigation of endogenous metabolism.

Disruption of Phthorimaea operculella (Lepidoptera: Gelechiidae) oviposition by the application of host plant volatiles.

BACKGROUNDPhthorimaea operculella is a key pest of potato. The authors characterised the P. operculella olfactory system, selected the most bioactive host plant volatiles and evaluated their potential application in pest management. The electrophysiological responses of olfactory receptor neurons (ORNs) housed in long sensilla trichodea of P. operculella to plant volatiles and the two main sex pheromone components were evaluated by the single-cell recording (SCR) technique. The four most SCR-active volatiles were tested in a laboratory oviposition bioassay and under storage warehouse conditions.RESULTSThe sensitivity of sensilla trichodea to short-chained aldehydes and alcohols and the existence of ORNs tuned to pheromones in females were characterised. Male recordings revealed at least two types of ORN, each of which typically responded to one of the two pheromone components. Hexanal, octanal, nonanal and 1-octen-3-ol significantly disrupted the egg-laying behaviour in a dose-dependent manner. Octanal reduced the P. operculella infestation rate when used under storage conditions.CONCLUSIONSThis work provides new information on the perception of plant volatiles and sex pheromones by P. operculella. Laboratory and warehouse experiments show that the use of hexanal, octanal, nonanal and 1-octen-3-ol as host recognition disruptants and/or oviposition deterrents for P. operculella control appears to be a promising strategy. © 2013 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

PWE-011 Charting the Volatile Organic Metabolome (VOM): A Comparison of Murine and Human Faeces

IntroductionThe metabolome is important in the development of IBD and colorectal cancer. It may be studied using gas chromatography mass spectrometry (GCMS) or electronic noses that sniff the volatile organic...

The mechanism of discrimination between oxidized and reduced coenzyme in the aldehyde dehydrogenase domain of Aldh1l1

Aldh1l1, also known as 10-formyltetrahydrofolate dehydrogenase (FDH), contains the carboxy-terminal domain (Ct-FDH), which is a structural and functional homolog of aldehyde dehydrogenases (ALDHs). This domain is capable of catalyzing the NADP+-dependent oxidation of short chain aldehydes to their corresponding acids, and similar to most ALDHs it has two conserved catalytic residues, Cys707 and Glu673. Previously, we demonstrated that in the Ct-FDH mechanism these residues define the conformation of the bound coenzyme and the affinity of its interaction with the protein. Specifically, the replacement of Cys707 with an alanine resulted in the enzyme lacking the ability to differentiate between the oxidized and reduced coenzyme. We suggested that this was due to the loss of a covalent bond between the cysteine and the C4N atom of nicotinamide ring of NADP+ formed during Ct-FDH catalysis. To obtain further insight into the functional significance of the covalent bond between Cys707 and the coenzyme, and the overall role of the two catalytic residues in the coenzyme binding and positioning, we have now solved crystal structures of Ct-FDH in the complex with thio-NADP+ and the complexes of the C707S mutant with NADP+ and NADPH. This study has allowed us to trap the coenzyme in the contracted conformation, which provided a snapshot of the conformational processing of the coenzyme during the transition from oxidized to reduced form. Overall, the results of this study further support the previously proposed mechanism by which Cys707 helps to differentiate between the oxidized and reduced coenzyme during ALDH catalysis.

Overexpression of hydroperoxide lyase, peroxygenase and epoxide hydrolase in tobacco for the biotechnological production of flavours and polymer precursors

Plants produce short-chain aldehydes and hydroxy fatty acids, which are important industrial materials, through the lipoxygenase pathway. Based on the information that lipoxygenase activity is up-regulated in tobacco leaves upon infection with tobacco mosaic virus (TMV), we introduced a melon hydroperoxide lyase (CmHPL) gene, a tomato peroxygenase (SlPXG) gene and a potato epoxide hydrolase (StEH) into tobacco leaves using a TMV-based viral vector system to afford aldehyde and hydroxy fatty acid production. Ten days after infiltration, tobacco leaves infiltrated with CmHPL displayed high enzyme activities of 9-LOX and 9-HPL, which could efficiently transform linoleic acid into C(9) aldehydes. Protein extracts prepared from 1 g of CmHPL-infiltrated tobacco leaves (fresh weight) in combination with protein extracts prepared from 1 g of control vector-infiltrated tobacco leaves (as an additional 9-LOX source) produced 758 ± 75 μg total C(9) aldehydes in 30 min. The yield of C(9) aldehydes from linoleic acid was 60%. Besides, leaves infiltrated with SlPXG and StEH showed considerable enzyme activities of 9-LOX/PXG and 9-LOX/EH, respectively, enabling the production of 9,12,13-trihydroxy-10(E)-octadecenoic acid from linoleic acid. Protein extracts prepared from 1 g of SlPXG-infiltrated tobacco leaves (fresh weight) in combination with protein extracts prepared from 1 g of StEH-infiltrated tobacco leaves produced 1738 ± 27 μg total 9,12,13-trihydroxy-10(E)-octadecenoic acid isomers in 30 min. The yield of trihydroxyoctadecenoic acids from linoleic acid was 58%. C(9) aldehydes and trihydroxy fatty acids could likely be produced on a larger scale using this expression system with many advantages including easy handling, time-saving and low production cost.

Carbonaceous species and humic like substances (HULIS) in Arctic snowpack during OASIS field campaign in Barrow

Snowpacks contain many carbonaceous species that can potentially impact on snow albedo and arctic atmospheric chemistry. During the OASIS field campaign, in March and April 2009, Elemental Carbon (EC), Water insoluble Organic Carbon (WinOC) and Dissolved Organic Carbon (DOC) were investigated in various types of snow: precipitating snows, remobilized snows, wind slabs and depth hoars. EC was found to represent less than 5% of the Total Carbon Content (TCC = EC + WinOC + DOC), whereas WinOC was found to represent an unusual 28 to 42% of TCC. Snow type was used to infer physical processes influencing the evolution of different fractions of DOC. DOC is highest in soil influenced indurated depth hoar layers due to specific wind related formation mechanisms in the early season. Apart from this specific snow type, DOC is found to decrease from precipitating snow to remobilized snow to regular depth hoar. This decrease is interpreted as due to cleaving photochemistry and physical equilibration of the most volatile fraction of DOC. Depending on the relative proportions of diamond dust and fresh snow in the deposition of the seasonal snowpack, we estimate that 31 to 76% of DOC deposited to the snowpack is reemitted back to the boundary layer. Under the assumption that this reemission is purely photochemical, we estimate an average flux of VOC out of the snowpack of 20 to 170 μgC m−2 h−1. Humic like substances (HULIS), short chain diacids and aldehydes are quantified, and showed to represent altogether a modest (&lt;20%) proportion of DOC, and less than 10% of DOC + WinOC. HULIS optical properties are measured and could be consistent with aged biomass burning or a possible marine source.

Theoretical study of the reaction mechanism and kinetics of low-molecular-weight atmospheric aldehydes (C1–C4) with NO2

Accurate description of atmospheric reactions of a series of low-molecular-weight (LMW) aldehydes (C1–C4) with NO2 has been modeled using a direct dynamic approach. The profiles of the potential energy surface were constructed at the BMC-CCSD//MPWB1K/6-311G(d,p) level of theory, and two different pathways have been found: H-abstraction and NO2-addition. The modeling results found that the contribution of NO2-addition reaction pathway to the total rate constant is very small and thus this kind of pathway is insignificant in atmospheric conditions. The predicted H-abstraction products are mainly reactive acyl radical and nitrous acid (HONO) which is very mutagenic and carcinogenic pollutant as well as the precursor of acid deposition. The rate constants of both pathways were also deduced by using canonical variational transition state theory incorporating with the small curvature tunneling correction within 200–360 and 360–2000 K. Theoretical overall rate constants are in good agreement with the available experimental values, whose increase in the order of kformaldehyde < kacetaldehyde < kpropanal < kbutanal, implying that relative long-chain LMW aldehydes are more reactive toward NO2 than those short-chain LMW aldehydes in the atmospheric condition. At 298 K, the total rate constants of LMW aldehydes (C1–C4) with NO2 are obtained as 1.65 × 10−25, 1.43 × 10−24, 3.39 × 10−24 and 1.83 × 10−23 cm3 molecule−1 s−1, respectively.