Article

Determination of myoglobin concentration in blood-perfused tissue.

Faculty of Human Sciences, Institute of Human and Social Science, Kanazawa University, Kanazawa, Japan.
Arbeitsphysiologie (Impact Factor: 2.66). 10/2008; 104(1):41-8. DOI: 10.1007/s00421-008-0775-x
Source: PubMed

ABSTRACT The standard method for determining the myoglobin (Mb) concentration in blood-perfused tissue often relies on a simple but clever differencing algorithm of the optical spectra, as proposed by Reynafarje. However, the underlying assumptions of the differencing algorithm do not always lead to an accurate assessment of Mb concentration in blood-perfused tissue. Consequently, the erroneous data becloud the understanding of Mb function and oxygen transport in the cell. The present study has examined the Mb concentration in buffer and blood-perfused mouse heart. In buffer-perfused heart containing no hemoglobin (Hb), the optical differencing method yields a tissue Mb concentration of 0.26 mM. In blood-perfused tissue, the method leads to an overestimation of Mb. However, using the distinct (1)H NMR signals of MbCO and HbCO yields a Mb concentration of 0.26 mM in both buffer- and blood-perfused myocardium. Given the NMR and optical data, a computer simulation analysis has identified some error sources in the optical differencing algorithm and has suggested a simple modification that can improve the Mb determination. Even though the present study has determined a higher Mb concentration than previously reported, it does not alter significantly the equipoise PO(2), the PO(2) where Mb and O(2) contribute equally to the O(2) flux. It also suggests that any Mb increase with exercise training does not necessarily enhance the intracellular O(2) delivery.

0 Bookmarks
 · 
136 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: Previous studies have shown that palmitate (PA) can bind specifically and non-specifically to Fe(III)MbCN. The present study has observed PA interaction with physiological states of Fe(II)Mb, and the observations support the hypothesis that Mb may have a potential role in facilitating intracellular fatty acid transport. 1H NMR spectra measurements of the Mb signal during PA titration show signal changes consistent with specific and non-specific binding. Palmitate (PA) interacts differently with physiological states of Mb. Deoxy Mb does not interact specifically or non-specifically with PA, while the carbonmonoxy myoglobin (MbCO) interaction with PA decreases the intensity of selective signals and produces a 0.15ppmupfield shift of the PAmethylene peak. The selective signal change upon PA titration provides a basis to determine an apparent PA binding constant,which serves to create a model comparing the competitive PA binding and facilitated fatty acid transport of Mb and fatty acid binding protein(FABP). Given contrasting PA interaction of ligated vs. unligated Mb, the cellular fatty acid binding protein(FABP) and Mb concentration in the cell, the reported cellular diffusion coefficients, the PA dissociation constants from ligated Mb and FABP, a fatty acid flux model suggests that Mb can compete with FABP transporting cellular fatty acid. Under oxygenated conditions and continuous energy demand, Mb dependent fatty acid transport could influence the cell's preference for carbohydrate or fatty acid as a fuel source and regulate fatty acid metabolism.
    Biochimica et Biophysica Acta 01/2014; 1840(1):656-66. · 4.66 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Pressure-volume curves of the lungs and chest wall require knowledge of an effective 'average' pleural pressure (Pplav), and are usually estimated using esophageal pressure as PLes-V and PWes-V curves. Such estimates could be misleading when Ppl becomes spatially non-uniform with lung lavage or shape distortion of the chest. We therefore measured PLes-V and PWes-V curves in conditions causing spatial non-uniformity of Ppl in rats. PLes-V curves of normal lungs were unchanged by chest removal. Lung lavage depressed PLes-V but not PWes-V curves to lower volumes, and chest removal after lavage increased volumes at PL≥15cmH2O by relieving distortion of the mechanically heterogeneous lungs. Chest wall distortion by ribcage compression or abdominal distension depressed PWes-V curves and PLes-V curves of normal lungs only at PL≥3cmH2O. In conclusion, Pes reflects Pplav with normal and mechanically heterogeneous lungs. With chest wall distortion and dependent deformation of the normal lung, changes of PLes-V curves are qualitatively consistent with greater work of inflation.
    Respiratory Physiology & Neurobiology 02/2013; · 2.05 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Myoglobin (Mb) is used to study protein structure/function and cellular O2 transport.•Mb O2 affinity determination is complicated by Hb contamination and Mb autoxidation.•We developed novel methods to efficiently extract Mb and measure Mb O2 affinity.•We produced purified Mb quickly with little autoxidation using one buffer solution.•O2 affinity of extracted cow Mb was identical to commercially prepared horse heart Mb.
    Protein Expression and Purification 11/2014; · 1.43 Impact Factor

Full-text (2 Sources)

Download
81 Downloads
Available from
May 21, 2014