Myoglobin mass spectrum

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%. 

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

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. 

Figure 5-4. Electrospray ionization mass spectrum of horse heart myoglobin.

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. 

Figure 2.24. Mass spectrum of singly and doubly protonated horse heart myoglobin ions obtained by DIT.

Fig. 5.12 The mass spectrum of myoglobin showing multiply charged ions (upper trace) and the deconvoluted spectrum showing the molecular weight (lower trace).

Fig. 10.12 ESI-FT-ICR mass spectra of (a) the fluoroacetic acid, pH 3. The inserts show native intact hem-protein complex of horse isotopic resolutions for the 9- and 1 7-fold heart myoglobin (b) spectrum ofthe denatured protonated molecular ions [145]. apoprotein upon dissociation of hem in tri-...

Mao, D. Ding, C. Douglas, D.J. Hydrogen/deuterium exchange of myoglobin ions in a linear quadrupole ion trap. Rapid Commun. Mass Spectrum. 2002,16, 1941-1945. 

FIGURE 1.6 Electrospray ionization (ESI) mass spectrum and deconvoluted data for apo-myoglobin. 

FIGURE 3.11 Electrospray mass spectrum of apo-myoglobin and the deconvoluted data giving the molecular mass of the protein. 

Figure 2.19. ESI mass spectrum of horse heart myoglobin. (Reproduced from C. Dass, Principles and Practice of Biological Mass Spectrometry, Wiley-Interscience, 2001.)...

Figure 6 Electrospray mass spectrum of the protein myoglobin, FW 16950. The numbers at the peaks denote the number of charges on the ions.

Figure 1.4 UV-MALDI mass spectrum of myoglobin. Matrix DHBs (2,5-dihydroxybenzoic acid [2,5-DHB] plus 2-hydroxy-5-methoxysalicylic acid [MSA] 9 1 [w/w]). Wavelength, 337nm mass analyzer, reflectron TOF.

Figure 2 Mass spectrum of horse heart myoglobin obtained by ESI-MS. Sample introduction was performed via a syringe pump at 6 nL/min at a concentration of 2 pmol/nL (CH3CN/H2O 1 1). The two most abundant multiply charged molecular ions are shown and the measured mass is given as compared with the calculated molecular weight. The standard deviation of 100ppm (1.8 Da) results from the calculation of the average mass based on all of the multiply charged molecular ions (see text for details of the calculation).

Figure 18.8. High-resolution nanoESI mass spectrum of equine myoglobin (0.2 mg mL pH 7.5, lOmM NH4HCO3) with a 7-tesla FT-ICR mass spectrometer (lonSpec Ultima).

The results obtained by DIT are of high interest mass resolution >17,000 and the capability for high mass range at low trapping voltage and fixed q0 (see, e.g., the spectrum of horse heart myoglobin reported in Fig. 2.24) make this system deeply different from the ITs described... 

Fig. 10. Mass spectra of from MALDIMS, and from ESIMS. For MALDIMS the mass scale was calibrated with myoglobin ions as an internal standard. For ESIMS the mass scale was calibrated externally using the doubly charged and singly charged ions of gramicidin S. The right hand panel of the ESIMS spectrum shows the deconvoluted spectrum, giving measured molecular weights for the mtgor species, which differ by one hexose. Deviations from the calculated values are shown in parentheses.

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