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Purification of the complex of cathepsin L and the MHC class II‐associated invariant chain fragment from human kidney
Author(s) -
Ogrinc Tadeja,
Dolenc Iztok,
Ritonja Anka,
Turk Vito
Publication year - 1993
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(93)80875-u
Subject(s) - cd74 , cathepsin , chemistry , mhc class ii , cathepsin l , cathepsin d , peptide sequence , microbiology and biotechnology , major histocompatibility complex , biochemistry , biology , enzyme , gene
The complex of cathepsin L and the fragment of the MHC class II‐associated invariant chain was purified from human kidney. M r , of the complex, as determined by gel filtration, is about 40,000. Both components were identified by amino acid and sequence analyses. The bound invariant chain fragment is almost identical to the additional segment found in p41, but not in the p31 form of the invariant chain. The complex has significantly enhanced stability at neutral and slightly alkaline pH, and reduced proteolytic activity against the synthetic substrate Z‐Phe‐Arg‐MCA compared to free cathepsin L. The complex exhibits no enzymatic activity against the protein substrate azocasein. For the first time, the invariant chain was found in a complex with a protein, which was not an MHC molecule.