Angiotensin converting-like enzymes from urine of untreated renovascular hypertensive and normal patients: purification and characterization

Angiotensin converting-like enzymes (ACE) were isolated from urine of normal (P0N, P1N and P2N) and untreated renovascular hypertensive (P-0, P-1 and P-2) patients, The urine were submitted to ion exchange chromatography. Enzymes P-0 and P0N were eluted with the equilibrium buffer (0.02 M Tris-HCl, pH 7.0), while P-1, P1N, P-2 and P2N with ionic strength linear gradient of 0.02-0.5 M Tris-HCl, pH 7.0 in 0.7 mS and P-2 and P2N in 1.2 mS conductance. The active fractions were submitted to gel filtration in Sephadex G-150, equilibrated and performed with 0.05 M Tris-HCl/0.15 M NaCl buffer, pH 8.0. All enzymes were homogeneous when analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) (molecular mass: P-0, P-1 and P2N about 60 kDa; P-1, 95 kDa and P21N 170 kDa). The enzymes were recognized by Y1 polyclonal antibody raised against human renal ACE, The K-M values were in millimolar order for hippuryl-L-His-Leu (HHL) while for benzyloxycarbonyl-Phe-L-His-Leu (ZFHL) they were in 10(-4) M order. The enzymes were able to hydrolyze angiotensin I (AI) (P-0 and P0N about 25%, P-1 and P1N about 70%, P-2 100% and P2N 66%) and bradykinin (BK) (P0N 22%, P1N 81%, P2N 62%, P-0 and P-1 50% and P2 35%), and their activities were inhibited by captopril. (C) 2000 Elsevier Science B.V. All rights reserved.