[Comparison of the properties of L-threonine dehydratase isolated from the livers of intact, adrenalectomized or cortisol-treated rats].

L-Threonine dehydratase preparations were isolated from liver of intact, treated with hydrocortisone and adrenalectomized rats. These preparations had different properties in stability, sensitivity to proteases and kinetic patterns. The preparations possessed also serine dehydratase activity, and the ratio threonine: serine activities was modified during the procedure of enzyme purification. It appears that the hormones affect not only the amount of enzyme proteins, but the qualitative properties of these proteins.