From Early Discoveries To The Emergence Of An Ubiquitous Protein Family

As with many enzyme families, for the peroxiredoxins the discovery, structural and biochemical characterization of a protein with unknown function preceded the assignment of enzymatic activity. Thus, the single torus protein/torin, a decameric ring-like protein complex isolated from human erythrocytes, was first revealed by transmission electron microscopy (TEM) (Harris, 1968; Harris, 1969). The native sedimentation coefficient of torin was determined as ~ 11S (Harris, 1971), the subunit mass by SDS-PAGE as ~ 20kDa (Harris and Naeem, 1978) and the isoelectric point (pi) as ~ pH 4.8 (Harris, 1980). Torin, also characterized as the erythrocyte membrane Band 8 protein, is now known to be identical to the erythrocyte peroxiredoxin ii. Some confusion was exhibited in these early studies, because of the co-isolation of a hollow cylindrical protein complex from erythrocytes, now known to be the 20S proteasome. Indeed, this confusion was further perpetuated in the literature by the isolation from bovine mitochondria of a protein complex

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