Myoglobin preparation

Artificial myoglobins prepared with modified and metalloporphyrins. Biochemistry, 9,2268-2275. Dorr, F. (1971). Polarized light in spectroscopy and photochemistry, in A.A. Lamola (ed.), Creation and Detection of the Excited States, pp. 53-122, Dekker, New York. 

Initial imidazole concentration 70.0 moles/m3 Initial myoglobin concentration 0.114 mole/m3 (Initial conditions refer to those used in preparing the system for study, not those at the moment the equilibrium is perturbed.)... 

Iwai, K., Fukuoka, S.-I., Fushiki, T., Kido, K., Sengoku, Y., and Semba, T. (1988) Preparation of a verifiable peptide-protein immunogen direction-controlled conjugation of a synthetic fragment of the monitor peptide with myoglobin and application for sequence analysis. Anal. Biochem. 171, 277-282. 

Figure 2.9. Schematic of a matrix-assisted laser desorption/ionization (MALDI) event. The SEM micrograph depicts sinapinic acid-equine myoglobin crystal from a sample prepared according to the dried drop sample preparation method. In the desorption event neutral matrix molecules (M), positive matrix ions (M+), negative matrix ions (M-), neutral analyte molecules (N), positive analyte ions (+), and negative analyte ions (-) are created and/or transferred to the gas phase. Reprinted from A. Westman-Brinkmalm and G. Brinkmalm (2002). In Mass Spectrometry and Hyphenated Techniques in Neuropeptide Research, J. Silberring and R. Ekman (eds.) New York John Wiley Sons, 47-105. With permission of John Wiley Sons, Inc.

Four spin-labelled derivatives of sperm whale metmyoglobin were prepared by site-directed mutagenesis.101 Cyanide anion or imidazole was added to prepare low-spin Fe(III). Iron relaxation rates were measured by saturation recovery or inversion recovery between 5 and 17 K and by analysis of the temperature-dependent contribution to the CW line widths of the iron signal at 20 to 160 K. The nitroxyl 7i values in spin-labelled Zn-substituted myoglobin were measured to provide values in the absence of interaction with the more rapidly-relaxing Fe(III). The full shapes of the nitroxyl saturation-recovery curves for the spin-... 

Myoglobin (from sperm whale muscle). [9047-17-0]] Mr -17,000. Purified by CM-cellulose chromatography and Sephadex G-50 followed by chromatography on Amberlite IRC-50 Type III or BioRex 70 (<400mesh). The crystalline product as a paste in saturated (NH4)2SO4 at pH 6.5-7.0 may be stored at 4° for at least 4 years unchanged, but must not be kept in a freezer. [Anres and Atassi Biochemistry 12 942 1980, Edmundson Biochemical Preparations 12 41 7968]. 

Although the final concentration of myoglobin desired in the experiment must be considered, a concentrated myoglobin stock solution ( 40 mM) is easily prepared and reduced. Additionally, 0.15 mM myoglobin is routinely used in the authors experiments, as this represents an average concentration for myoglobin in different bovine skeletal muscles (Rickansrud and Henrickson, 1967). 

Meat discoloration studies typically involve a maximum of 5 days, with discoloration analy-sis being performed every day or on alternate days. The actual experimental time involved in the objective assessment of discoloration is not extensive and depends on the number of samples being analyzed. Colorimetric measurements with hand-held colorimeters are very rapid (three measurements per meat surface in < 1 min). Spectral scans of meat surfaces require 1 to 2 min. Extraction and analysis of ground meat products has the added step of homogenization and filtration prior to spectrophotometry, but relative to many laboratory procedures, this is relatively quick. Isolation and purification of preparative amounts of myoglobin requires only 2 to 3 days once appropriate preparations are made. Finally, metmyoglobin can be reduced to oxymyoglobin in 15 to 20 min. 

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