Mass spectral analysis of eleven analogs of vitamin A

Reid, Robert H.; Nelson, E. C.; Mitchell, Earl D.; McGregor, M. L.; Waller, George R.; John, K. V.

doi:10.1007/bf02532712

Cited by 17 publications

(5 citation statements)

References 14 publications

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“…The value agreed with that of 5,6-epoxyretinoic acid already reported by John et al (1967). An electron-impact mass spectrum had typical prominent ions of 5,6-epoxyretinoic acid (Reid et al, 1973) at m/z 316 (M+), 301 (M+-15) and 271 (M+-45) ( Fig. 3a).…”

Section: Resultssupporting

confidence: 89%

Haemoglobin-catalysed retinoic acid 5,6-epoxidation

Iwahashi¹,

Ikeda²,

Kido³

1985

Biochemical Journal

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Examination of the subcellular distribution of retinoic acid 5,6-epoxidase activity in rat liver and human liver homogenates showed that there is a prominent peak of activity in a high-density fraction. A corresponding peak was also detected in rat blood and human blood. Retinoic acid 5,6-epoxidation was catalysed by human blood cells but not by human plasma, and purified human haemoglobin also catalysed the epoxidation of retinoic acid to 5,6-epoxyretinoic acid. These results suggest that retinoic acid 5,6-epoxidase activity in human liver and rat liver homogenates is partially due to the presence of residual blood cells, and particularly haemoglobin, in the homogenates. In the retinoic acid 5,6-epoxidation catalysed by human haemoglobin, molecular O2 was required and its reaction was stimulated by Triton X-100. Boiling of haemoglobin solution resulted in an 94% decrease in the activity. NADPH (1 mM) and NADH (1 mM) completely [2-mercaptoethanol (5 mM) almost completely] inhibited the 5,6-epoxidation catalysed by haemoglobin, but catalase, superoxide dismutase and mannitol showed no inhibitory effect. CN- ion (100 mM) inhibited the reaction, but N3- ion (100 mM) did not.

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Section: Resultssupporting

confidence: 89%

Haemoglobin-catalysed retinoic acid 5,6-epoxidation

Iwahashi¹,

Ikeda²,

Kido³

1985

Biochemical Journal

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“…The mass spectrum of methyl-8m (Figure 7 mje 312 (M+ -H2O) suggests that the additional oxygen atom is probably not present as a hydroxyl group. In addition, the series of ions at mje 271,217,177,165,164,149, and 135 represents a pattern observed for 5,6 or 5,8 oxygenated retinoic acid derivatives (Reid et al, 1973). The mass spectrum of methyl 5,6-epoxyretinoate (Figure 7, bottom panel) is indistinguishable from that of methyl-8m• Thus, spectral evidence indicates that metabolite 8m is 5,6-epoxyretinoic acid.…”

Section: Resultsmentioning

confidence: 85%

Isolation and identification of 5,6-epoxyretinoic acid: a biologically active metabolite of retinoic acid

McCormick¹,

Napoli²,

Schnoes³

et al. 1978

Biochemistry

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A highly biologically active metabolite of retinoic acid (8III) has been isolated in pure form from intestinal mucosa of vitamin A deficient rats given [3H]retinoic acid. This metabolite has been positively identified as 5, 6-epoxyretinoic acid based on the ultraviolet absorption spectrum and mass spectrum of its methylated derivative. This identification was confirmed by cochromatography of the methylated metabolite and synthetic methyl 5, 6-epoxyretinoate on reverse-phase and straight-phase high-pressure liquid chromatography. The 5, 6-epoxyretinoic acid is a true in vivo generated metabolite of retinoic acid and not an artifact of the isolation procedure. In addition, 5, 8-oxyretinoic acid previously isolated in this laboratory from intestinal mucosa was probably generated from 5, 6-epoxyretinoic acid by the acidic conditions used in the extraction and isolation of the 5, 8-oxyretinoic acid.

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“…Therefore reversed-phase high-performance liquid chromatography (HPLC) coupled with UV/visible detection is commonly used for isolation, separation, and identification of retinyl esters. − Limitations of HPLC separation and the similarity of absorption spectra, however, do not allow for unequivocal characterization. These disadvantages can be eliminated by employing mass spectrometry (MS), which provides both molecular weight information and characteristic fragment ion information helpful for structural elucidation. − …”

mentioning

confidence: 99%

“…Various kinds of ionization techniques, including electron impact (EI), − positive or negative chemical ionization (PCI, NCI), , laser desorption/ionization (LDI), and electrospray (ESI) 16 mass spectrometry have been applied for analysis of underivatized retinol and related retinoids. Mass spectrometry of retinoids suffers particularly from their thermal instability.…”

mentioning

confidence: 99%

High-Performance Liquid Chromatography and Laser Desorption/Ionization Mass Spectrometry of Retinyl Esters

et al. 1997

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Laser desorption/ionization mass spectrometry (LDI-MS) at 337 nm laser wavelength was used to analyze retinol and several long-chain fatty acid esters of retinol. Employing this ionization technique helped to overcome the inherent problems resulting from thermal instability of retinyl esters which render this group of compounds rather difficult for standard ionization techniques. Mass spectra were recorded with a linear time-of-flight instrument in positive ion mode. Under these conditions, retinyl esters formed radical molecular ions (M.+) and in addition fragmented by elimination of the fatty acyl chain to uniformly form a peak at m/z = 269 u. The elimination of carbon dioxide was also observed in the spectra. The method is suitable to identify specific retinyl esters in complex mixtures of these compounds. A gradient reversed-phase high-performance liquid chromatography (HPLC) is described for the separation of retinol and 15 related fatty acid esters within 28 min. HPLC was applied to separate retinyl esters from rat liver extracts. The LDI mass spectrum of the collected HPLC fraction of rat liver extract showed the molecular parent ions of retinyl myristate, pentadecanoate, palmitoleate, palmitate, heptadecanoate, linoleate, oleate, stearate, and 3,4-didehydroretinyl palmitate. LDI-MS was found to be more appropriate than matrix-assisted laser desorption/ionization for the described analytical task.

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Mass spectral analysis of eleven analogs of vitamin A

Cited by 17 publications

References 14 publications

Haemoglobin-catalysed retinoic acid 5,6-epoxidation

Haemoglobin-catalysed retinoic acid 5,6-epoxidation

Isolation and identification of 5,6-epoxyretinoic acid: a biologically active metabolite of retinoic acid

High-Performance Liquid Chromatography and Laser Desorption/Ionization Mass Spectrometry of Retinyl Esters

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