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Davies SS, Amarnath V, Montine KS, Bernoud-Hubac N, Boutaud O, Montine TJ, Roberts LJ. Effects of reactive gamma-ketoaldehydes formed by the isoprostane pathway (isoketals) and cyclooxygenase pathway (levuglandins) on proteasome function. FASEB J 2002; 16:715-7. [PMID: 11978738 DOI: 10.1096/fj.01-0696fje] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Oxidative stress can impair proteasome function, both of which are features of neurodegenerative diseases. Inhibition of proteasome function leads to protein accumulation and cell death. We discovered recently the formation of highly reactive g-ketoaldehydes, isoketals (IsoKs), and neuroketals (NeuroKs) as products of the isoprostane and neuroprostane pathways of free radical-induced lipid peroxidation that are analogous to cyclooxygenase-derived levuglandins (LGs). Because aldehydes that are much less reactive than IsoKs have been shown to inhibit proteasome function, we explored the ability of the proteasome to degrade IsoK-adducted proteins/peptides and the effect of IsoK and IsoK-adducted proteins/peptides on proteasome function. Adduction of IsoK to model proteasome substrates significantly reduced their rate of degradation by the 20S proteasome. The ability of IsoK to inhibit proteasome function directly was observed only at very high concentrations. However, at much lower concentrations, an IsoK-adducted protein (ovalbumin) and peptide (Ab1-40) significantly inhibited chymotrypsin-like activity of the 20S proteasome. Moreover, incubation of IsoK with P19 neuroglial cultures dose-dependently inhibited proteasome activity (IC50 = 330 nM) and induced cell death (LC50 = 670 nM). These findings suggest that IsoKs/NeuroKs/LGs can inhibit proteasome activity and, if overproduced, may have relevance to the pathogenesis of neurodegenerative diseases.
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Affiliation(s)
- Sean S Davies
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee 27232-6602, USA
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Bernoud-Hubac N, Davies SS, Boutaud O, Montine TJ, Roberts LJ. Formation of highly reactive gamma-ketoaldehydes (neuroketals) as products of the neuroprostane pathway. J Biol Chem 2001; 276:30964-70. [PMID: 11413140 DOI: 10.1074/jbc.m103768200] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Neuroprostanes are prostaglandin-like compounds produced by free radical-induced peroxidation of docosahexaenoic acid, which is highly enriched in the brain. We previously described the formation of highly reactive gamma-ketoaldehydes (isoketals) as products of the isoprostane pathway of free radical-induced peroxidation of arachidonic acid. We therefore explored whether isoketal-like compounds (neuroketals) are also formed via the neuroprostane pathway. Utilizing mass spectrometric analyses, neuroketals were found to be formed in abundance in vitro during oxidation of docosahexaenoic acid and were formed in greater abundance than isoketals during co-oxidation of docosahexaenoic and arachidonic acid. Neuroketals were shown to rapidly adduct to lysine, forming lactam and Schiff base adducts. Neuroketal lysyl-lactam protein adducts were detected in nonoxidized rat brain synaptosomes at a level of 0.09 ng/mg of protein, which increased 19-fold following oxidation in vitro. Neuroketal lysyl-lactam protein adducts were also detected in vivo in normal human brain at a level of 9.9 +/- 3.7 ng/g of brain tissue. These studies identify a new class of highly reactive molecules that may participate in the formation of protein adducts and protein-protein cross-links in neurodegenerative diseases and contribute to the injurious effects of other oxidative pathologies in the brain.
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Affiliation(s)
- N Bernoud-Hubac
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee 37232-6602, USA
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53
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Salomon RG, Batyreva E, Kaur K, Sprecher DL, Schreiber MJ, Crabb JW, Penn MS, DiCorletoe AM, Hazen SL, Podrez EA. Isolevuglandin-protein adducts in humans: products of free radical-induced lipid oxidation through the isoprostane pathway. BIOCHIMICA ET BIOPHYSICA ACTA 2000; 1485:225-35. [PMID: 10832102 DOI: 10.1016/s1388-1981(00)00038-x] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
A family of extremely reactive electrophiles, isolevuglandins (isoLGs), is generated in vivo by free radical-induced lipid oxidation and rearrangement of endoperoxide intermediates of the isoprostane pathway. Protein adducts of two different oxidized lipids, isoLGE(2) and iso[4]LGE(2), and the corresponding autoantibodies are present in human blood. Western blot analysis of a polyacrylamide gel electrophoresis gel detects several immunoreactive plasma proteins. Only a minor fraction of the isoLG-protein modifications is associated with low density lipoprotein since mean levels were decreased only 20-22% by immunoprecipitation of apolipoprotein B (apoB). Mean levels of both isoLGE(2) and iso[4]LGE(2)-protein adducts in plasma from patients with atherosclerosis (AS) (n=16) or end-stage renal disease (RD) (n=8) are about twice those in healthy individuals (n=25). These elevated levels are not related to variations in age, total cholesterol or apoB. A linear correlation (r=0.79) between plasma isoLGE(2) and iso[4]LGE(2)-protein adduct levels in all 49 individuals is consistent with a common free radical-induced mechanism for the production of both oxidized lipids in vivo. The correlation is even stronger (r=0.86) for patients with AS or RD. That isoLG-protein adduct levels are more strongly correlated with disease than are total cholesterol or apoB suggests an independent defect that results in an abnormally high level of oxidative injury associated with AS and RD.
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Affiliation(s)
- R G Salomon
- Department of Chemistry, Case Western Reserve University, Cleveland, OH 44106-7078, USA.
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54
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Salomon RG, Sha W, Brame C, Kaur K, Subbanagounder G, O'Neil J, Hoff HF, Roberts LJ. Protein adducts of iso[4]levuglandin E2, a product of the isoprostane pathway, in oxidized low density lipoprotein. J Biol Chem 1999; 274:20271-80. [PMID: 10400646 DOI: 10.1074/jbc.274.29.20271] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Levuglandin (LG) E2, a cytotoxic seco prostanoic acid co-generated with prostaglandins by nonenzymatic rearrangements of the cyclooxygenase-derived endoperoxide, prostaglandin H2, avidly binds to proteins. That LGE2-protein adducts can also be generated nonenzymatically is demonstrated by their production during free radical-induced oxidation of low density lipoprotein (LDL). Like oxidized LDL, LGE2-LDL, but not native LDL, undergoes receptor-mediated uptake and impaired processing by macrophage cells. Since radical-induced lipid oxidation produces isomers of prostaglandins, isoprostanes (isoPs), via endoperoxide intermediates, we postulated previously that a similar family of LG isomers, isoLGs, is cogenerated with isoPs. Now iso[4]LGE2-protein epitopes produced by radical-induced oxidation of arachidonic acid in the presence of protein were detected with an enzyme-linked immunosorbent assay. Iso[4]LGE2-protein epitopes are also generated during free radical-induced oxidation of LDL. All of the LGE2 isomers generated upon oxidation of LDL are efficiently sequestered by covalent adduction with LDL-based amino groups. The potent electrophilic reactivity of iso-LGs can be anticipated to have biological consequences beyond their obvious potential as markers for specific arachidonate-derived protein modifications that may be of value for the quantitative assessment of oxidative injury.
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Affiliation(s)
- R G Salomon
- Department of Chemistry, Case Western Reserve University, Cleveland, Ohio 44106-7078, USA.
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55
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Roberts LJ, Salomon RG, Morrow JD, Brame CJ. New developments in the isoprostane pathway: identification of novel highly reactive gamma-ketoaldehydes (isolevuglandins) and characterization of their protein adducts. FASEB J 1999; 13:1157-68. [PMID: 10385607 DOI: 10.1096/fasebj.13.10.1157] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The bicyclic endoperoxide prostaglandin (PG) H2 undergoes nonenzymatic rearrangement not only to PGE2 and PGD2, but also to levuglandins (LG) E2 and D2, which are highly reactive gamma-ketoaldehydes. Isoprostanes (IsoPs) are PG-like compounds that are produced by nonenzymatic peroxidation of arachidonic acid. PGH2-like endoperoxides are intermediates in this pathway. Therefore, we explored whether the IsoP endoperoxides also undergo rearrangement to form IsoLGs. Oxidation of arachidonic acid in vitro resulted in the formation of abundant quantities of compounds that were established to be IsoLGs by using mass spectrometric analyses. However, the formation of IsoLGs could not be detected in biological systems subjected to an oxidant stress. We hypothesized that this was due to extremely rapid adduction of IsoLGs to proteins. This notion was supported by the finding that LGE2 adducted to albumin at a rate that exceeded that of 4-hydroxynonenal by several orders of magnitude: >50% of LGE2 had adducted within 20 s. We therefore undertook to characterize the nature of LG adducts. Using liquid chromatography electrospray tandem mass spectrometry, we established that LGs form oxidized pyrrole adducts (lactams and hydroxylactams) with the epsilon-amino group of lysine. Oxidation of low density lipoprotein resulted in readily detectable IsoLG adducts on apolipoprotein B after enzymatic digestion of the protein to individual amino acids. These studies identify a novel class of ketoaldehydes produced by the IsoP pathway that form covalent protein adducts at a rate that greatly exceeds that of other known aldehyde products of lipid peroxidation. Elucidation of the nature of the adducts formed by IsoLGs provides the basis to explore the formation of IsoLGs in vivo and investigate the potential biological ramifications of their formation in settings of oxidant injury.
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Affiliation(s)
- L J Roberts
- Departments of Pharmacology and Medicine, Vanderbilt University, Nashville, Tennessee, 37232-6602, USA.
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56
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Brame CJ, Salomon RG, Morrow JD, Roberts LJ. Identification of extremely reactive gamma-ketoaldehydes (isolevuglandins) as products of the isoprostane pathway and characterization of their lysyl protein adducts. J Biol Chem 1999; 274:13139-46. [PMID: 10224068 DOI: 10.1074/jbc.274.19.13139] [Citation(s) in RCA: 141] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Isoprostanes are prostaglandin-like compounds produced by non-enzymatic peroxidation of arachidonic acid. The cyclooxygenase-derived endoperoxide, prostaglandin H2, can undergo rearrangement to highly reactive gamma-ketoaldehyde secoprostanoids (levuglandin E2 and D2). 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 E2 adducted to albumin within 20 s, whereas approximately 50% 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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Affiliation(s)
- C J Brame
- Departments of Pharmacology and Medicine, Vanderbilt University, Nashville, Tennessee 37232-6602, USA
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57
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Affiliation(s)
- Subhas C. Roy
- Department of Chemistry, Case Western Reserve University, Cleveland, Ohio 44106-7078
| | - Laxmi Nagarajan
- Department of Chemistry, Case Western Reserve University, Cleveland, Ohio 44106-7078
| | - Robert G. Salomon
- Department of Chemistry, Case Western Reserve University, Cleveland, Ohio 44106-7078
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58
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Ong CW, Chen CM, Wang LH, Jan JJ, Shieh PC. Efficient Synthesis of Pyrroles from Chemoselective Addition of Primary Amines to 1,6-Dioxo-2,4-dienes. J Org Chem 1998. [DOI: 10.1021/jo981566x] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Chi Wi Ong
- Department of Chemistry, National Sun Yat Sen University, Kaohsiung, Taiwan
| | - Chong Meng Chen
- Department of Chemistry, National Sun Yat Sen University, Kaohsiung, Taiwan
| | - Long Hu Wang
- Department of Chemistry, National Sun Yat Sen University, Kaohsiung, Taiwan
| | - Jiing Jyh Jan
- Department of Chemistry, National Sun Yat Sen University, Kaohsiung, Taiwan
| | - Po Chuen Shieh
- Department of Pharmacy, Ta Jen Pharmaceutical Junior College, Ping Tung, Taiwan
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59
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Podrez EA, O'Neil J, Salomon RG, Schreiber MJ, Hoff HF. Measurement of oxidation in plasma Lp(a) in CAPD patients using a novel ELISA. Kidney Int 1998; 54:637-45. [PMID: 9690232 DOI: 10.1046/j.1523-1755.1998.00034.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
BACKGROUND LGE2 is produced by the cyclooxygenase- or free radical-mediated modification of arachidonate and is formed during the oxidation of low density lipoprotein (LDL) with subsequent adduction to lysine residues in apo B. We have developed a sensitive enzyme-linked sandwich immunosorbent assay (ELISA) for detection and measurement of LGE2-protein adducts as an estimate of oxidation of plasma LDL and Lp(a). METHODS The assay employs rabbit polyclonal antibodies directed against LGE2-protein adducts that form pyrroles, and alkaline phosphatase-conjugated polyclonal antibodies specific for apo B or apo (a). It demonstrates a high degree of specificity, sensitivity and validity. RESULTS Epitopes characteristic for LGE2-pyrroles were quantified in patients with end-stage renal disease (ESRD) that had undergone continuous ambulatory peritoneal dialysis (CAPD) and in a gender- and age-matched control population. In addition to finding that both LDL and Lp(a) levels were elevated in CAPD patients, we also found that plasma Lp(a) but not LDL was more oxidized in CAPD patients when compared to corresponding lipoproteins from healthy subjects. Using density gradient ultra-centrifugation of plasma samples, we found that modified Lp(a) floats at the same density as total Lp(a). CONCLUSIONS The results of this study demonstrate that oxidation of plasma Lp(a) is a characteristic of ESRD patients undergoing CAPD. This ELISA may be useful for further investigations on oxidation of lipoproteins in the circulation of specific patient populations.
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Affiliation(s)
- E A Podrez
- Department of Cell Biology, Lerner Research Institute, Cleveland Clinic Foundation, Ohio, USA
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60
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Subbanagounder G, Salomon RG, Murthi KK, Brame C, Roberts LJ. Total Synthesis of Iso[4]-levuglandin E2. J Org Chem 1997. [DOI: 10.1021/jo970858f] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Ganesamoorthy Subbanagounder
- Department of Chemistry, Case Western Reserve University, Cleveland, Ohio 44106-7078, and the Departments of Pharmacology and Medicine, Vanderbilt University, Nashville, Tennessee 37232-6602
| | - Robert G. Salomon
- Department of Chemistry, Case Western Reserve University, Cleveland, Ohio 44106-7078, and the Departments of Pharmacology and Medicine, Vanderbilt University, Nashville, Tennessee 37232-6602
| | - Krishna K. Murthi
- Department of Chemistry, Case Western Reserve University, Cleveland, Ohio 44106-7078, and the Departments of Pharmacology and Medicine, Vanderbilt University, Nashville, Tennessee 37232-6602
| | - Cynthia Brame
- Department of Chemistry, Case Western Reserve University, Cleveland, Ohio 44106-7078, and the Departments of Pharmacology and Medicine, Vanderbilt University, Nashville, Tennessee 37232-6602
| | - L. Jackson Roberts
- Department of Chemistry, Case Western Reserve University, Cleveland, Ohio 44106-7078, and the Departments of Pharmacology and Medicine, Vanderbilt University, Nashville, Tennessee 37232-6602
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61
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Hoppe G, Subbanagounder G, O'Neil J, Salomon RG, Hoff HF. Macrophage recognition of LDL modified by levuglandin E2, an oxidation product of arachidonic acid. BIOCHIMICA ET BIOPHYSICA ACTA 1997; 1344:1-5. [PMID: 9022751 DOI: 10.1016/s0005-2760(96)00160-9] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Levuglandin (LG) E2, a secoprostanoic acid levulinaldehyde derivative, is a product of free radical oxidation that forms covalent adducts with lysyl residues on proteins. Treatment of LDL with LGE2 leads to uptake and degradation by mouse peritoneal macrophages. Oxidized LDL, but not acetyl LDL efficiently competed for binding and uptake of LGE2-modified 125I-LDL. This result suggests that LGE2-modified LDL was recognized by a class of scavenger receptor that demonstrated ligand specificity for oxidized LDL but not for acetyl LDL.
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Affiliation(s)
- G Hoppe
- Department of Cell Biology, Research Institute, Cleveland Clinic Foundation, OH 44195, USA
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62
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Murthi KK, Friedman LR, Oleinick NL, Salomon RG. Formation of DNA-protein cross-links in mammalian cells by levuglandin E2. Biochemistry 1993; 32:4090-7. [PMID: 8471616 DOI: 10.1021/bi00066a034] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Levuglandin E2 (LGE2), a rearrangement product derived from the prostaglandin endoperoxide, PGH2, causes repair-resistant DNA-protein cross-links and cell death (LD50 = 230 nM) in V79 Chinese hamster lung fibroblasts. The half-life for sequestration of LGE2 by covalent binding to cellular nucleophiles is at least an hour for 10 microM LG. This suggests that the in vivo production and distribution of free LGs should be measurable on this time scale. Following removal of the LGE2 and the return of the cultures to normal growth medium, additional DNA-protein cross-links continued to form over the ensuing 6-24 h. The results suggest that LG adducts to DNA or protein are not repaired, but react further at sites on protein or DNA in close proximity to the initial adducts, forming cross-links in a slow phase of the process.
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Affiliation(s)
- K K Murthi
- Department of Chemistry, Case Western Reserve University, Cleveland, Ohio 44106
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63
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Schmidley JW, Dadson J, Iyer RS, Salomon RG. Brain tissue injury and blood-brain barrier opening induced by injection of LGE2 or PGE2. Prostaglandins Leukot Essent Fatty Acids 1992; 47:105-10. [PMID: 1461920 DOI: 10.1016/0952-3278(92)90145-9] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The hypothesis that the accumulation of prostaglandin (PG)E2 during reperfusion of severely ischemic tissue contributes to a breakdown in the blood-brain barrier (BBB) was expanded to include a parallel role for levuglandins(LGs), gamma-ketoaldehydes produced by rearrangement of PGH2. LGE2 was shown to be more potent than PGE2 in causing breakdown of the BBB when injected intrahemispherically. Brain tissue necrosis was clearly evident with total doses of levuglandin as low as 100 nmole.
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Affiliation(s)
- J W Schmidley
- Department of Neurology, Case Western Reserve University, Cleveland, Ohio 44106-2699
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64
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Jirousek MR, Murthi KK, Salomon RG. Electrophilic levuglandin E2-protein adducts bind glycine: a model for protein crosslinking. PROSTAGLANDINS 1990; 40:187-203. [PMID: 2217833 DOI: 10.1016/0090-6980(90)90083-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Prevention by glycine of protein crosslinking which accompanies binding of levuglandin E2 (LGE2) is shown to involve binding of glycine with the protein-LGE2 adduct. With ovalbumin, the LGE2 adduct initially binds nearly 2 equivalents of glycine, but the capacity to bind glycine decreases with time reflecting a competition, inter alia, with crosslinking.
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Affiliation(s)
- M R Jirousek
- Department of Chemistry, Case Western Reserve University, Cleveland, Ohio 44106-2699
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65
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Abstract
Levuglandin E2 (LGE2), a gamma-ketoaldehyde produced by rearrangement of the prostaglandin endoperoxide PGH2 under the aqueous conditions of its biosynthesis, causes extensive intermolecular crosslinking of ovalbumin at pH 6 or pH 7 and 37 degrees C. The time dependence of protein oligomerization is monitored by SDS-PAGE. Effects of pH and concentration on the extent of LGE2-induced crosslinking are examined. The efficacy of LGE2 for inducing crosslinking is compared with other oxidative metabolites of arachidonic acid (AA), including the prostaglandins PGE2, PGD2, PGA2, PGB2, and PGF2 alpha, as well as malondialdehyde and E-4-hydroxy-non-2-enal. LGE2 is orders of magnitude more effective in crosslinking protein than any other cyclooxygenase or lipoxygenase metabolite of AA tested.
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Affiliation(s)
- R S Iyer
- Department of Chemistry, Case Western University, Cleveland, Ohio 44106-2699
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66
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Jirousek MR, Salomon RG. Purification of a Water-Sensitive Natural Product with an Aprotic CPC Solvent System. ACTA ACUST UNITED AC 1988. [DOI: 10.1080/01483918808076743] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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67
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Salomon RG, Jirousek MR, Ghosh S, Sharma RB. Prostaglandin endoperoxides 21. Covalent binding of levuglandin E2 with proteins. PROSTAGLANDINS 1987; 34:643-56. [PMID: 3481092 DOI: 10.1016/0090-6980(87)90289-9] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Levuglandin E2 (LGE2), a gamma-ketoaldehyde produced by rearrangement of the prostaglandin endoperoxide PGH2 under the aqueous conditions of its biosynthesis, binds covalently with ram seminal vesicle microsomes. Totally synthetic 5,6-ditritio-LGE2 was prepared and used to determine that rapid covalent binding of LGE2 (initially 800 microM) occurs with 6.4 microM bovine serum albumin (greater than 10 equiv within 1 min) which approaches saturation (approximately 16 equiv) after 40 min at 37 degrees C.
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Affiliation(s)
- R G Salomon
- Department of Chemistry, Case Western Reserve University, Cleveland, Ohio 44106-2699
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