“Prorenin activation by a novel enzyme

VINCENT PAULA; ADLER CONRADO; AVILA CÉSAR; GUARDIA CECILIA; DE VITO EDUARDO

Santiago de Chile, Chile.

Congreso; XIV Scientific Meeting of the Inter American Society of Hypertension" y "XV Meeting of the Chilean Society of Hypertension"; 2001

IASH

PRORENIN ACTIVATION BY A NOVEL ENZYME (PreR-Co) P. Vincent*, C. Adler*, C. Avila*, C. Guardia, E. De Vito INSIBIO (UNT-CONICET) - Chacabuco 461 – 4000 –Tucumán - Argentina.         Email: paulav@unt.edu.ar     A rat plasma enzyme (PreR-Co) capable of activating renal prorenin but not plasma prorenin was previously isolated. The purposes of the present study were: I) To purify rat renal prorenin to study the reaction product after PreR-Co treatment. II) To study PreR-Co action over prorenin secreted from renal slices. Renal prorenin and renin were purified by several steps including Sepharose-H77 chromatography. Prorenin was treated with PreR-Co and applied to H77-column. The eluted fraction, recognized by a specific renin antibody in a western blot, have a molecular mass equal to rat renin. The difference between the molecular mass of this fraction and prorenin is coincident with that of the propeptide. Renal slices were incubated during 120 min. The renal extracts and the incubation liquids were activated by PreR-Co and trypsin. Higher activation with PreR-Co than that of trypsin was obtained in the tissue (6.4 and 2.4 times respectively), but the contrary occurred in the incubation liquids (2.5 and 3.9 times respectively). These results show: 1- PreR-Co is a prorenin convertase. 2- The recently secreted prorenin was weakly activated by PreR-Co indicating that structural changes might occur during its release and then completed by plasmatic factors which prevent the exposure of the active centre.