T. Miyake

T. Miyake led the byline of a 1977 report, with C. K. Kung and E. Goldwasser, describing purification of human erythropoietin. Ion-exchange chromatography, gel filtration and other separations yielded an active hormone preparation with $930$-fold purification and $21\%$ activity recovery.^[ref]

Purity and recovery measure different achievements. For a hypothetical starting sample with $100$ activity units, $21\%$ recovery leaves $21$ units even if most unwanted proteins have been removed. A high purification factor therefore does not mean that nearly all of the starting erythropoietin survived.