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Volume 357, Issue 2 p. 129-134
Research letter
Free Access

Molecular cloning of human cathepsin O, a novel endoproteinase and homologue of rabbit OC2

Guo-Ping Shi

Guo-Ping Shi

Physiology Program, Harvard School of Public Health, Boston, MA 02115, USA

Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA

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Harold A. Chapman

Harold A. Chapman

Physiology Program, Harvard School of Public Health, Boston, MA 02115, USA

Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA

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Srirama M. Bhairi

Srirama M. Bhairi

Department of Medicine, The University of Michigan Medical Center, Ann Arbor, MI 48109, USA

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Carrie DeLeeuw

Carrie DeLeeuw

Department of Medicine, The University of Michigan Medical Center, Ann Arbor, MI 48109, USA

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Vivek Y. Reddy

Vivek Y. Reddy

Department of Medicine, The University of Michigan Medical Center, Ann Arbor, MI 48109, USA

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Stephen J. Weiss

Stephen J. Weiss

Department of Medicine, The University of Michigan Medical Center, Ann Arbor, MI 48109, USA

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First published: January 03, 1995
Citations: 137
Corresponding authors. H.A. Chapman, MD, Respiratory Division, Brigham and Women's Hospital, 75 Francis Street, Boston, MA 02115, USA. Fax: (1) (617) 232-4623; S.J. Weiss, MD, Hematology/Oncology, University of Michigan Medical Center, 1150 W. Medical Center Dr., Ann Arbor, MI 48109-0668, USA. Fax: (1) (313) 764-0101.

Abstract

A 1670-bp cDNA coding for a novel human cysteine protease has been isolated from a monocyte-derived macrophage cDNA library. This cDNA predicts a 329-amino acid preprocathepsin with more than 50% identity to both human cathepsin S and cathepsin L and 94% identity to a rabbit cDNA, termed OC2, recently isolated from osteoclasts. Based on its high homology to OC2, we have named the human enzyme cathepsin O. Cathepsin O mRNA was identified as a single ∼1.7 kb transcript in cultures of 15-day-old monocyte-derived macrophages, but was not expressed in human monocytes or alveolar macrophages. When transfected into COS-7 cells, cathepsin O displayed potent endoprotease activity against fibrinogen at acid pH. This novel endoprotease may play an important role in extracellular matrix degradation.