CSF : Vol. 25 (2000) , No. 5 pp.309-315

Insulin-Degrading Enzyme Exists Inside of Rat Liver Peroxisomes and Degrades Oxidized Proteins

Masashi Morita¹⁾, Igor V Kurochkin²⁾, Kiyoto Motojima²⁾, Sataro Goto²⁾, Tatsuya Takano³⁾, Shoji Okamura¹⁾, Ryuichiro Sato⁴⁾, Sadaki Yokota⁵⁾ and Tsuneo Imanaka¹⁾

1) Department of Biological Chemistry, Faculty of Pharmaceutical Sciences, Toyama Medical and Pharmaceutical University
2) Department of Biochemistry, School of Pharmaceutical Sciences, Toho University
3) Department of Microbiology and Molecular Pathology, Faculty of Pharmaceutical Sciences, Teikyo University
4) Department of Applied Biological Chemistry, Graduate School of Agriculture and Life Sciences, The University of Tokyo
5) Biological Laboratory, Yamanashi Medical University

ABSTRACT. Insulin-degrading enzyme (IDE) was detected by immunoblot analysis in highly purified rat liver peroxisomes. IDE in the peroxisomal fraction was resistant to proteolysis by trypsin and chymotrypsin under conditions where the peroxisomal membranes remained intact. After sonication of the peroxisomal fraction, IDE was recovered in the supernatant fraction. Further, the localization of IDE in the peroxisomes was shown by immunoelectron microscopy. In addition, IDE isolated from peroxisomes degraded insulin as well as oxidized lysozyme as a model substrate for oxidized proteins. These results suggest that IDE exists in an active form in the matrix of rat liver peroxisomes and is involved in elimination of oxidized proteins in peroxisomes.

Key words: insulin-degrading enzyme/ subcellular localization/ peroxisomes/ proteolysis/ oxidized proteins

	To cite this article:
	Masashi Morita, Igor V Kurochkin, Kiyoto Motojima, Sataro Goto, Tatsuya Takano, Shoji Okamura, Ryuichiro Sato, Sadaki Yokota and Tsuneo Imanaka; “Insulin-Degrading Enzyme Exists Inside of Rat Liver Peroxisomes and Degrades Oxidized Proteins”. Cell Struct. Funct., Vol. 25, 309-315 (2000) .

	doi:10.1247/csf.25.309
	JOI JST.JSTAGE/csf/25.309