Stabilized denatured lipoprotein and process for producing the same

Denatured lipoprotein excelling in stability of prolonged preservation (namely exhibiting only sparing liability to induce denaturation of lipoprotein) and used as a standard substance for the determination of denatured lipoprotein in blood or the determination of the physiological activity of the lipoprotein and a method for the production thereof are provided. The method for the production of the stabilized denatured lipoprotein comprises artificially denaturing lipoprotein, thereby obtaining denatured lipoprotein, freeze-drying the denatured lipoprotein or performing a process including at least one freezing operation on a solution containing denatured lipoprotein thereby denaturing the lipoprotein contained in the solution and obtaining denatured lipoprotein and further freeze-drying the denatured lipoprotein.