Determination of choline in erythrocytes using high-resolution proton nuclear magnetic resonance spectroscopy: Comparison with a choline oxidase method

Beilharz, Georg R.; Middlehurst, Carl R.; Kuchel, Philip W.; Hunt, Glenn E.; Johnson, Gordon

doi:10.1016/0003-2697(84)90093-9

Cited by 14 publications

(5 citation statements)

References 22 publications

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“…The spectra acquired from rat brain homogenates show considerable similarity to those obtained from rabbit brains (Middlehurst et al, 1984). However, there are some major species differences in neurochemicals, such as, for example, the relative abundance of taurine ( Fig.…”

Section: Discussionmentioning

confidence: 73%

“…g . , Beilharz et al, 1984). In common with human erythrocytes , the intensity of the creatine methyl resonance is invariant over several hours incubation of the tissue at 37°C.…”

Section: Prolidase Kineticsmentioning

confidence: 96%

“…'H NMR spectra were recorded at 37°C using a Bruker WM400 spectrometer operated in the pulsed Fourier transform mode. The acquisition parameters in the 180"-T~-~O O -T > -180"-~,-AQ IRSE pulse sequence were the same as those used for spectra from rabbit brain homogenate (Middlehurst et al, 1984). An interscan delay of 1 s, T , = 0.06 s, and T?…”

Section: 'H Nmr Measurementsmentioning

confidence: 99%

“…The intensities of IRSE signals from a given chemical species are dependent on the concentration of the species, its longitudinal (TI) and transverse (T2) relaxation times, the pulse sequence delay times ( T~ and T~) , and the nature and extent of spin-spin coupling. However, under controlled conditions, the dependence of peak intensity on concentration can be calibrated by addition of known amounts of metabolites to a sample (Beilharz et al, 1984).…”

mentioning

confidence: 99%

“…'H NMR IRSE spectra were recently obtained from rabbit brain homogenates (Middlehurst et al, 1984) and at that time diverse applications of this technique were mooted. The optimum parameters for the acquisition of IRSE spectra from rat brain homogenate are reported and the resonances are assigned to various neurochemicals.…”

mentioning

confidence: 99%

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Studies of Rat Brain Metabolism Using Proton Nuclear Magnetic Resonance: Spectral Assignments and Monitoring of Prolidase, Acetylcholinesterase, and Glutaminase

Middlehurst¹,

King²,

Beilharz³

et al. 1984

Journal of Neurochemistry

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The first application of inversion-recovery spin-echo proton nuclear magnetic resonance spectroscopy to the monitoring of reactions in rat brain preparations is presented. The initial report of the assignment of proton spin-echo nuclear magnetic resonance spectra from rabbit brain homogenates (C. R. Middlehurst et al., J. Neurochem. 42, 878-879, 1984) was used to assist in the assignment of spectra acquired from rat brain homogenates that were obtained from animals killed by cervical fracture or focussed microwave irradiation. Microwave-irradiated brains were divided into four major anatomical regions. Differences in metabolite levels were detected when spectra from fresh tissue and from various regions were compared. The in situ steady-state kinetics of prolidase in whole brain homogenate was determined. The procedure relies on the spectral differences between enzyme substrates and reaction products. The concentration dependence of the rate of hydrolysis of glycyl-L-proline was discribable by the Michaelis-Menten expression with a Michaelis constant of 1.90 mmol L-1 and a maximal velocity of 9.30 mumol min-1 mg-1 protein. The reactions catalysed by glutaminase and acetylcholinesterase in the brain were also monitored.

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Section: Discussionmentioning

confidence: 73%

“…g . , Beilharz et al, 1984). In common with human erythrocytes , the intensity of the creatine methyl resonance is invariant over several hours incubation of the tissue at 37°C.…”

Section: Prolidase Kineticsmentioning

confidence: 96%

Section: 'H Nmr Measurementsmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Studies of Rat Brain Metabolism Using Proton Nuclear Magnetic Resonance: Spectral Assignments and Monitoring of Prolidase, Acetylcholinesterase, and Glutaminase

Middlehurst¹,

King²,

Beilharz³

et al. 1984

Journal of Neurochemistry

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No evidence for bradykinin hydrolysis in human erythrocyte suspensions: H NMR studies

1987

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In view of their permeability to small peptides, it has been postulated that human erythrocytes may play a role in terminating the action of some circulating peptide hormones. Work using classical paper chromatographic techniques for detecting free amino acids indicated that the octapeptide, des-(Arg9)-bradykinin, enters these cells and its amino-terminal arginine residue is released by cytosolic aminopeptidase-P. We have used 1H NMR to monitor directly the release of arginine from bradykinin. The hydrolytic reaction rate in hemolysates, with an initial peptide concentration of 13.0 mmol l-1 was 6.5 mmol (1 packed red cell)-1 h-1. But no reaction was evident after a 4.5-h incubation with intact cells, thus contradicting the earlier suggestion that erythrocytes are involved in the primary inactivation of this hormone. This is consistent with our previous findings that the pentapeptide leu-enkephalin fails to enter human erythrocytes but that its lower-order degradation products may do so.

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Determination of erythrocyte pyrimidine 5′-nucleotidase activity by31P nuclear magnetic resonance: Comparison of normal controls and multiple sclerosis patients

et al. 1986

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A technique to assay erythrocyte pyrimidine 5'-nucleotidase activity in situ using 31P nuclear magnetic resonance spectroscopy is presented. The assay is chemically specific, simple and applicable to untreated lysates. A comparison of enzyme levels in normal controls and in multiple sclerosis patients employing the assay yielded no significant differences between both groups. Difficulties encountered in the quantitative analysis of the assay using 1H-NMR spectroscopy are briefly discussed.

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Determination of choline in erythrocytes using high-resolution proton nuclear magnetic resonance spectroscopy: Comparison with a choline oxidase method

Cited by 14 publications

References 22 publications

Studies of Rat Brain Metabolism Using Proton Nuclear Magnetic Resonance: Spectral Assignments and Monitoring of Prolidase, Acetylcholinesterase, and Glutaminase

Studies of Rat Brain Metabolism Using Proton Nuclear Magnetic Resonance: Spectral Assignments and Monitoring of Prolidase, Acetylcholinesterase, and Glutaminase

No evidence for bradykinin hydrolysis in human erythrocyte suspensions: H NMR studies

Determination of erythrocyte pyrimidine 5′-nucleotidase activity by31P nuclear magnetic resonance: Comparison of normal controls and multiple sclerosis patients

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