Microburger Biochemistry: Extraction and Spectral Characterization of Myoglyobin from Hamburger
Sheri A. Bylkas
Department of Chemistry, Vassar College, Poughkeepsie, New York 12601
Laura A. Andersson
(914) 437-7000; E.mail: LANDERSS@Vassar.edu. Former address: Department of Biochemistry; 103 Willard Hall, Kansas State University, Manhattan, KS 66506
This experiment provides a demonstration of useful biochemical methods at a Basic or Advanced Level, depending upon the available spectrophotometric equipment. The protocol combines protein extraction, ox-i-dation and reduction, and simple spectroscopic analysis, as well as gel filtration chromatography and generation/analysis of spectral scans. Mammalian myoglobin (Mb) is a monomeric O2-binding protein that functions in muscle to store oxygen. The single iron protoporphyrin IX (heme) group is bound to protein by the amino acid Histidine93. The common, stable forms, Met-Mb and Oxy-Mb are studied because in a non-living system, red Oxy-Mb is converted to brown Met-Mb as bound O2 molecule is released. Mb is easily extracted from steak, to illustrate and address why fresh meat is red and aged meat is brown; the protein has unique spectral properties that are diagnostic for characterization of sample identity. After application of heme redox chemical methods, the MetMb or OxyMb samples can be studied spectroscopically. The color change between Oxy-Mb and Met-Mb is dramatic (illustrating bright red fresh meat vs. brown older meat), and method(s) used in this laboratory are simple, inexpensive, and non-harmful to the student.
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Bylkas, Sheri A.; Andersson, Laura A. J. Chem. Educ.1997 74 426.
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