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Characterization of a cathepsin‐H‐like enzyme from a human melanoma cell line
Author(s) -
Tsushima Hirofumi,
Ueki Ayako,
Matsuoka Yasuo,
Mihara Hisashi,
HopsuHavu Väinö K.
Publication year - 1991
Publication title -
international journal of cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.475
H-Index - 234
eISSN - 1097-0215
pISSN - 0020-7136
DOI - 10.1002/ijc.2910480516
Subject(s) - enzyme , biochemistry , extracellular , cathepsin o , cathepsin , cathepsin a , cathepsin d , molecular mass , microbiology and biotechnology , cathepsin l1 , fibronectin , cell culture , laminin , chemistry , enzyme assay , cathepsin e , biology , extracellular matrix , genetics
A cathepsin‐H‐like enzyme has been isolated from cultured human melanoma cells (G 361 cell line). The enzyme is similar to cathepsin H(s) of normal tissues in molecular weight, enzymatic characteristics (substrates, inhibitors, pH optima, K m values), and immunoreactivity. The inactive form of the enzyme with a molecular mass of 40 kDa has been found in the culture medium. The inactive enzyme is activated by acid pH, pepsin, and cathepsin‐D‐like enzyme treatments and converted into a form with a molecular mass of 28 kDa. The activated extracellular cathepsin‐H‐like enzyme and the active intracellular enzyme exhibit the same characteristics. The melanoma‐derived cathepsin‐H‐like enzyme degrade fibrinogen and fibronectin, but not laminin or type‐IV collagen. We conclude that the extracellular cathepsin‐H‐like enzyme may have important functions, together with other proteinases, in the destruction of extracellular matrix components, thus enabling proliferation, migration, and metastasis to occur.