ACTIVATION OF RENAL RENIN BY A PROTEIN PLASMA FRACTION - A NOVEL ENZYMATIC MECHANISM

Citation
E. Devito et al., ACTIVATION OF RENAL RENIN BY A PROTEIN PLASMA FRACTION - A NOVEL ENZYMATIC MECHANISM, Comparative biochemistry and physiology. B. Comparative biochemistry, 113(2), 1996, pp. 433-438
Citations number
21
Categorie Soggetti
Biology
ISSN journal
03050491
Volume
113
Issue
2
Year of publication
1996
Pages
433 - 438
Database
ISI
SICI code
0305-0491(1996)113:2<433:AORRBA>2.0.ZU;2-U
Abstract
A 3-fold increase in active renin was found after a kidney cortex extr act was incubated with plasma from either normal or nephrectomized rat s (0.34 +/- 0.04 to 1.34 +/- 0.08 and 1.60 +/- 0.06 mu g Angiotenson I /mg tissue/hr, respectively). A plasma protein that activates renal re nin was purified 900-fold. Purification of the protein was achieved by a combination of ammonium sulfate fractionation, molecular filtration on Sephacryl S-200 HR and ion-exchange chromatography on Mono Q HR 5/ 5 associated to an fast performance liquid chromatography (FPLC) syste m. The protein shows a molecular weight of similar to 54,000 Da. Renin activation was not inhibited by serine protease inhibitors, such as p henylmethyl sulfonylfluoride, aprotinin, soybean trypsin inhibitor and N-tosyl-L-phenylalanine chloromethyl ketone or by the cystein proteas e inhibitors N-ethylmaleimide and leupeptin. By using enzyme inhibitor s, it was found that the activation process is not mediated by kallikr ein, plasmin, tonin, cathepsin B or trypsin-like enzymes. From these r esults, we conclude that there is in circulating plasma a previously u nidentified enzyme capable of activating inactive kidney renin. Howeve r, the possibility that this protein acts by activating the renin-subs trate reaction cannot be dismissed.