Covalent binding of a neurotoxic n-hexane metabolite: Conversion of primary amines to substituted pyrrole adducts by 2,5-hexanedione

DeCaprio, Anthony P.; Olajos, Eugene J.; Weber, Peter

doi:10.1016/0041-008x(82)90389-1

Cited by 137 publications

(53 citation statements)

References 19 publications

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“…Based on previous data reported by Salomon and colleagues (20), we predicted that a major protein adduct would be a pyrrole produced from reaction of LGE 2 with the ⑀-amino group of lysyl residues. In initial studies, we used free lysine to model this reaction which seemed valid because the ␣-amino group of free lysine is only about 1/6 as reactive as the ⑀-amino group (16). The predicted [MH] ϩ ion for the LGE 2 -lysine pyrrole adduct is m/z 463.…”

Section: Methodsmentioning

confidence: 99%

“…The mixture was gently bubbled with N 2 until the ether evaporated and then incubated for 2 h at room temperature to hydrolyze IsoLG protein adducts that may have formed with IsoLG esterified to LDL lipids. The pH was then adjusted to 7.5, and the protein was subjected to complete enzymatic digestion to individual amino acids as described (16). Briefly, the protein concentration was adjusted to 1 mg/ml.…”

Section: Methodsmentioning

confidence: 99%

“…We considered these experiments to be very informative since, as mentioned previously, our attempts to detect unadducted free IsoLGs during oxidation of LDL were not successful. For these analyses, as outlined under "Experimental Procedures," LDL was oxidized for 4 h with AAPH and delipidated, and the apoB-100 protein was then digested to individual amino acids by sequential treatment with Pronase and leucine aminopeptidase (16). Na- pathway.…”

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confidence: 99%

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Identification of Extremely Reactive γ-Ketoaldehydes (Isolevuglandins) as Products of the Isoprostane Pathway and Characterization of Their Lysyl Protein Adducts

Brame

Salomon

Morrow

et al. 1999

Journal of Biological Chemistry

165

209

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Isoprostanes are prostaglandin-like compounds produced by non-enzymatic peroxidation of arachidonic acid. The cyclooxygenase-derived endoperoxide, prostaglandin H 2 , can undergo rearrangement to highly reactive ␥-ketoaldehyde secoprostanoids (levuglandin E 2 and D 2 ). We explored whether isoprostane endoperoxide intermediates also rearrange to levuglandin-like compounds (isolevuglandins). Formation of a series of isolevuglandins during oxidation of arachidonic acid in vitro was established utilizing a number of mass spectrometric analyses. However, these compounds could not be detected in free form in protein-containing biological systems, which we hypothesized was due to extremely rapid adduction to amines. This was supported by the finding that >60% of levuglandin E 2 adducted to albumin within 20 s, whereas ϳ50% of 4-hydroxynonenal still remained unadducted after 1 h. By utilizing electrospray tandem mass spectrometry, we established that these compounds form oxidized pyrrole adducts (lactams and hydroxylactams) with lysine. Formation of isolevuglandin-lysine adducts on apolipoprotein B was readily detected during oxidation of low density lipoprotein following enzymatic digestion of the protein to single amino acids. These studies identify a novel series of extremely reactive products of the isoprostane pathway that rapidly form covalent adducts with lysine residues on proteins. This provides the basis to explore the formation of isolevuglandins in vivo to investigate the potential biological ramifications of their formation in settings of oxidant injury.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

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Identification of Extremely Reactive γ-Ketoaldehydes (Isolevuglandins) as Products of the Isoprostane Pathway and Characterization of Their Lysyl Protein Adducts

Brame

Salomon

Morrow

et al. 1999

Journal of Biological Chemistry

165

209

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“…Although this neuropathy has been induced in humans and animals following exposure to several compounds, including n-hexane and methyl n-butyl ketone [Allen et al, 1975;Spencer et a]., 1980a], it has been established that HD is the ultimate toxic metabolite [Krasavage et al, 19801. HD reacts with lysyl residues on proteins to form pyrroles [DeCaprio et al, 1982;Graham et al, 19821, a reaction which has been utilized to quantify exposure [Anthony et al, 1983a;Pyle et al, 19921. It has also been suggested that pyrrole formation may alter the normal charge of neurofilarnents affecting their interactions with other components of the cytoskel-…”

Section: Introductionmentioning

confidence: 99%

Decreased levels of the high molecular weight subunit of neurofilaments and accelerated neurofilament transport during the recovery phase of 2,5‐hexanedione exposure

Pyle

Amarnath

Graham

et al. 1993

Cell Motil. Cytoskeleton

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The neurotoxicant 2,5-hexanedione (HD) causes the accumulation of neurofilaments in the distal axon and an acceleration of neurofilament transport proximal to the site of their accumulation. It has been proposed that the acceleration of transport is due to the direct reaction of HD with neurofilament proteins and, conversely, that this acceleration is a secondary response to the axon to injury. The objective of this study was to determine whether the response of axons to HD intoxication includes acceleration of neurofilament transport. Pulse labelling was used to analyze neurofilament transport in age-matched rats exposed to HD or PBS. The animals receiving HD were exposed either throughout the period of radiolabel transport, or prior to the pulse labeling of neurofilament proteins. If acceleration of the rate of neurofilament transport was due to the direct reaction of HD with proteins, then neurofilaments synthesized after the exposure period should travel at control rates, since these proteins would not have been exposed to the toxicant. After 28 days of transport, optic nerve proteins were examined using SDS-PAGE, fluorography, and computerized densitometry. In both HD-treated groups, neurofilament transport was accelerated relative to age-matched control animals. In addition, the amount of NFH was decreased relative to other neurofilament subunits. The combination of accelerated transport and a diminished proportion of NFH is similar to the observations of neurofilament axonal transport during growth and development. These observations suggest that this persistent, secondary effect is a reparative response to injury that recapitulates axonal growth and development.

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“…Another solvent, methyl n-butyl ketone, also causes a sensorimotor neuropathy, and the formation of the same toxic metabolite, 2,5-hexanedione, from both n-hexane and methyl n-butyl ketone has been firmly demonstrated (147). The pathogenesis of n-hexane neuropathy has been recently reviewed (148 (149,150). Experiments with diastereoisomers of 3,4-dimethyl-2,5-hexanedione have indicated that the formation of the pyrrole is a critical step in the sequence of events that result in the axonopathy (151).…”

Section: Styrenementioning

confidence: 99%

Biomarker Research in Neurotoxicology: The Role of Mechanistic Studies to Bridge the Gap between the Laboratory and Epidemiological Investigations

Costa¹

1996

Environmental Health Perspectives

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There is an increasing interest in the development and validation of biomarkers for use in biochemical/molecular epidemiological studies. Though the area of neurotoxicology has received much attention in the past several years, it still lags behind with regard to the development of biomarkers, particularly those of health effects and susceptibility. This review discusses several aspects of biomarker research as it relates to neurotoxic compounds and focuses on selected agents (organophosphorus insecticides, styrene, n-hexane, carbon disulfide, acrylamide), which have been the subject of a number of investigations in animals and humans. While traditional biomonitoring approaches and novel techniques (e.g., hemoglobin adducts) provide several measurements for monitoring exposure to neurotoxic chemicals, potential markers of genetic susceptibility have been seldom investigated in a neurotoxicology context. Furthermore, the complexity of the nervous system, together with the multiplicity of end points and the limited knowledge of the exact mechanism(s) of action of neurotoxicants, has led to only limited advancements in the development of biomarkers for neurotoxic effects. Significant progress in this area will depend upon an increased understanding of the cellular, biochemical, and molecular targets directly involved in neurotoxicity. Environ Health Perspect 1 04(Suppl 1): 55-67 (1996)

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Covalent binding of a neurotoxic n-hexane metabolite: Conversion of primary amines to substituted pyrrole adducts by 2,5-hexanedione

Cited by 137 publications

References 19 publications

Identification of Extremely Reactive γ-Ketoaldehydes (Isolevuglandins) as Products of the Isoprostane Pathway and Characterization of Their Lysyl Protein Adducts

Identification of Extremely Reactive γ-Ketoaldehydes (Isolevuglandins) as Products of the Isoprostane Pathway and Characterization of Their Lysyl Protein Adducts

Decreased levels of the high molecular weight subunit of neurofilaments and accelerated neurofilament transport during the recovery phase of 2,5‐hexanedione exposure

Biomarker Research in Neurotoxicology: The Role of Mechanistic Studies to Bridge the Gap between the Laboratory and Epidemiological Investigations

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