A HIRUDIN-SENSITIVE, GROWTH-RELATED PROTEINASE FROM HUMAN FIBROBLASTS

We have identified a hirudin-sensitive proteinase from human fibroblas ts. Inhibition of this enzyme results in partial inhibition of cell gr owth in culture. The enzyme has a molecular weight of about 38000, and can be isolated by affinity chromatography with a hirudin-agarose mat rix. The enzyme is apparently not closely related to thrombin, but doe s show a high level of amino acid sequence homology with fragments of a protein isolated from the synovial fluid of rheumatoid arthritis pat ients, which acts as a mitogen for human T lymphocytes.