Horse heart myoglobin

A sample of the protein, horse heart myoglobin, was dissolved in acidified aqueous acetonitrile (1% formic acid in HjO/CHjCN, 1 1 v/v) at a concentration of 20 pmol/1. This sample was injected into a flow of the same solvent passing at 5 pl/min into the electrospray source to give the mass spectrum of protonated molecular ions [M + nH] shown in (a). The measured ra/z values are given in the table (b), along with the number of protons (charges n) associated with each. The mean relative molecular mass (RMM) is 16,951,09 0.3 Da. Finally, the transformed spectrum, corresponding to the true relative molecular mass, is shown in (c) the observed value is close to that calculated (16,951.4), an error of only 0.002%. 

A typical electrospray spectrum of a high-molecular-weight material, i.e. that of horse heart myoglobin, is shown in Figure 4.11. Each of the ions observed arises from attachment of a different number of protons, and an equivalent number of charges, to the intact molecule. 

Figure 4.11 Electrospray spectrum of horse heart myoglobin.

Table 4.1 Molecular weight of horse heart myoglobin calculated from four adjacent pair of ions observed in its electrospray mass spectrum...

If we consider the electrospray spectrum of horse heart myoglobin shown pre-vionsly (see Figure 4.11), the information given in Table 4.1 may be obtained by application of the above equations. The precision and accuracy of these measurements are also shown in this table. 

Determine the charge state on the ion of m/z 1060.71 in the mass spectrum shown in Figure 4.11 by using the methodoiogy outlined above. From this, calculate the molecular weight of horse heart myoglobin. 

Konovalova, T. A., L. D. Kispert et al. (2004). Multifrequency high-field electron paramagnetic resonance characterization of the peroxyl radical. Location in horse heart myoglobin oxidized by H202. J. Phys. Chem. BIOS 11820-11826. 

I. Taniguchi, K. Watanabe, M. Tominaga, and F.M. Hawkridge, Direct electron transfer of horse heart myoglobin at an indium oxide electrode. J. Electroanal. Chem. 333, 331-338 (1992). 

Pig. 2. Comparison of the heme environments at the active sites of horse heart myoglobin 40) and yeast cytochrome c peroxidase 41). 

First resonance Raman spectra of hydroperoxo-ferric intermediate in heme proteins, together with EPR and absorption spectra, have been documented in 2003 using horse heart myoglobin.122 Only Fe-0 mode could be measured with Soret excitation... 

A Si micromixer was constmcted with seven vertical pillars (10 pm dia.) arranged perpendicular to the flow in a staggered fashion within a 450-pL mixing chamber, as shown in Figure 3.42. Turbulent mixing of sodium azide and horse heart myoglobin was achieved in 20 ps. This provided the fast mixing essential for a downstream freeze-quench procedure to trap metastable intermediates [472]. 

FIGURE 5.12 (a) ESI-mass spectrum of 5 pM horse heart myoglobin in 500 mM NaCl, 100 mM Tris, and 10 mM EDTA by direct infusion (b) ESI-mass spectrum of previous myoglobin sample after desalting, which was achieved by on-line microdialysis using 10 mM NH4OAc and 1% acetic acid as dialysis buffer [811]. Reprinted with permission from the American Chemical Society. 

Wan L, Twitchett MB, Eltis LD, Mauk AG, Smith M (1998) In vitro evolution of horse heart myoglobin to increase peroxidase activity. Proc Natl Acad Sci USA 95 12825-12831... 

Maurus R, Bogumil R, Nguyen NT, Mauk AG, Brayer G. Structural and spectroscopic studies of azide complexes of horse heart myoglobin and the His-64-Thr variant. Biochem J 1998 332 67-74. 

Horse heart myoglobin (ferric form, salt free, lyophilized) is purified by oxidation followed by separation, using column chromatography. A 1 mM solution of metmyoglobin is prepared and treated with an equimolar solution of ferricyanide. 

Trematode species from paramphistomum epiclitum. At 25 °C, pH 7.0. Sperm whale. Horse heart. Myoglobin reconstituted with an ironporphycene. At 25 °C, pH 7.0. 

Figure 7 Electrochemical FTIR absorbance spectra (top) and difference spectrum (reduced-oxidized, bottom) of horse heart myoglobin...

Figure 2. Utility of PE membrane over a large mass range. Spectra of bovine insulin (0.4 pmol/mm ), horse heart myoglobin (0.4 pmol/mm ), and bovine serum albuimin dimer (1 pmol/mm ) are displayed from top to bottom. All spectra are the summation of 20 shots, and are unsmoothed.

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