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Occurrence and Nature of Equine and Bovine Myoglobin Dimers

2005; Wiley; Volume: 10; Issue: 1 Linguagem: Inglês

10.1111/j.1432-1033.1969.tb00665.x

1432-1033

A. H. A. van den Oord, J. J. Wesdorp, A.F. van Dam, Jan A. Verheij,

Protein purification and stability

In commercial samples of equine myoglobin and samples of equine and bovine myoglobin prepared in the laboratory, a small amount of the protein was present as an aggregate. The presence of the myoglobin aggregate could be demonstrated by gel filtration on Sephadex G-100 Superfine, which also provided a means of isolating it. Gel filtration on Sephadex G-100 showed the molecular weights of the equine and bovine moyglobin aggregates to be about 35000 and 34000 respectively, thus supporting the hypothesis that they are dimers. This was confirmed for the equine myoglobin by ultracentrifugation measurements. The exact nature of the dimer cannot be specified. The conditions required for its formation in vitro and the fact that no traces of dimer could be detected in fresh muscle preclude the possibility of its natural occurrence. The spectral properties of the equine myoglobin dimer and its sedimentation and diffusion behaviour in the ultracentrifuge indicate, however, that the configuration of native monomeric myoglobin is essentially preserved in the dimer. Like their respective monomers, the dimers of equine and bovine myoglobin were shown by isoelectric fractionation to be microheterogeneous.