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Isolation of monocytic serine esterase and evaluation of its proteolytic activity
Author(s) -
Salmassi Ali,
Kreipe Hans,
Radzun Heinz J.,
Lilischkis Richard,
CharchinajadAmoey Madjid,
Zschunke Frank,
Buck Friedrich,
Lottspeich Friedrich,
Parwaresch M. Reza
Publication year - 1992
Publication title -
journal of leukocyte biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.819
H-Index - 191
eISSN - 1938-3673
pISSN - 0741-5400
DOI - 10.1002/jlb.51.4.409
Subject(s) - proteases , serine , biology , biochemistry , serine protease , esterase , protease , enzyme , monocyte , cytotoxicity , serine hydrolase , effector , isoelectric focusing , isoelectric point , microbiology and biotechnology , in vitro , immunology
Monocytes are characterized by high activity of α‐naphthyl acetate esterase (ANAE), distinguishing them from all other blood cells. The physiological function of this monocyte marker enzyme has not yet been elucidated. In this study ANAE's potential proteolytic activity was anlayzed because serine esterases/proteases can function as effector molecules in cell‐mediated cytotoxicity and because monocytes‐macrophages are known to exert cytotoxic effects on tumor cells. This enzyme was purified from the monocytic cell line U‐937 by preparative isoelectric focusing and a three‐step high‐performance liquid chromatography that conserved its catalytic activity. It has a molecular mass of 60 kd, and partial amino acid sequence revealed that the enzyme is not identical to known serine esterases/proteases. The purified enzyme failed to digest a couple of peptides, indicating lack of protease activity. In addition, the esterolytic activity of ANAE was not inhibited by protease inhibitors. The isolation and purification of ANAE enable further studies concerning its function in monocytes‐macrophages and its relation to monocytic cytotoxicity.