RESUMO
Activities of plasma membrane proteinases such as angiotensin-converting enzyme (ACE), aminopeptidases, and dipeptidyl peptidase IV (DPP-IV) were determined in lymphoid cells of various immunological phenotype which were obtained from 30 patients with lymphoproliferative diseases. The enzyme activities significantly varied depending on the immunological phenotype and stage of cell differentiation, but no correlation was found between activities of ACE, DPP-IV, and aminopeptidases in the cells of different type. The cell lysates studied contained at least two classes of aminopeptidases: metal- and sulfhydryl-dependent enzymes. A sulfhydryl-dependent aminopeptidase with activity optimum at pH 8. 5-9.0 was found for the first time and is suggested to be from a poorly studied aminopeptidase family. In addition to ACE, lysates of leukemic T- and B-cells were found to contain an inhibitor of ACE which was not previously described for these cells.
Assuntos
Aminopeptidases/metabolismo , Inibidores da Enzima Conversora de Angiotensina/farmacologia , Transtornos Linfoproliferativos/enzimologia , Peptidil Dipeptidase A/metabolismo , Antígenos CD/imunologia , Técnica Indireta de Fluorescência para Anticorpo , Humanos , Hidrólise , Transtornos Linfoproliferativos/imunologia , FenótipoRESUMO
Evidence is reported for the presence of dipeptidyl carboxypeptidase (peptidyldipeptide hydrolase, EC 3.4.15.1) and of inhibitor(s) of this enzyme in synovial fluids from patients with rheumatoid arthritis and gout.