Kageyama T, Yonezawa S, Ichinose M, Miki K, Moriyama A
Department of Cellular and Molecular Biology, Kyoto University, Inuyama, Japan.
Biochem Biophys Res Commun. 1996 Jun 25;223(3):549-53. doi: 10.1006/bbrc.1996.0932.
Seven peptides of 15-30 amino acid residues were synthesized that covered almost the entire sequence of the lumenal domain of the human invariant chain (Ii), and their hydrolysis by cathepsins D and E was investigated. Two sites were identified that were very susceptible to such cleavage. One site, the Leu174-Phe175 bond, was cleaved by both cathepsins, and the other site, the Met99-Gln100 bond, was specifically cleaved by cathepsin E. These two sites could be the sites at which native Ii is cleaved by aspartic proteinases. The cleavage of the Met99-Gln100 bond by cathepsin E might be important in the inactivation of Ii and its functional derivatives.
合成了7种由15 - 30个氨基酸残基组成的肽段，这些肽段几乎覆盖了人恒定链（Ii）腔结构域的整个序列，并研究了组织蛋白酶D和E对它们的水解作用。确定了两个对这种切割非常敏感的位点。一个位点，Leu174 - Phe175键，可被两种组织蛋白酶切割，另一个位点，Met99 - Gln100键，可被组织蛋白酶E特异性切割。这两个位点可能是天然Ii被天冬氨酸蛋白酶切割的位点。组织蛋白酶E对Met99 - Gln100键的切割可能在Ii及其功能衍生物的失活中起重要作用。
