<b>MAJOR KININASES IN RAT URINE ARE NEUTRAL ENDOPEPTIDASE AND CARBOXYPEPTIDASE Y-LIKE </b><b>EXOPEPTIDASE </b>

Abstract

Two types of kininases were separated from rat urine by gel-filtration on a column of Superdex 200 and characterized as a membrane-bound neutral endopeptidase (EC 3.4.24. ll) and a carboxypeptidase Y-like exopeptidase. The neutral endopeptidase which was found in a void volume fraction, liberated first Pheg-Arg9 and then Phe5-Serf-Pro? from bradykinin (BK)*. The kininase activity was inhibited by phosphoramidon and thiorphan but not by captopril. Another kininase with an apparent molecular weight of 93,000 cleaved rapidly BK into BKl-8 (des Argg BK) and BK1-7 (des Phe8~Arg9 BK) into BK1-6 (des Pro7-Phes-Argg BK). The kininase activity was inhibited by inhibitors for serine proteases and cysteine proteases and by metal ions (Co2+, Hg" or Ag+), but not by inhibitors for metal proteases. The kininase activity was also inhibited by a rabbit antipeptide IgG which was raised against a synthetic peptide with the amino acid sequence of human and mouse carboxypeptidase Y-like peptidases. These results indicate that the exopeptidase is not carboxypeptidases N or M but a member of a family of human and mouse carboxypeptidase Y-like exopeptidases which are identified as protective proteins associated with lysosomal ,8-galactosidase and neuraminidase or platelet peptidase with deamidase activity. When rat urine was incubated with BK, the generation of either BK1-8 or BKl-7 was inhibited in the presence of either DFP* or phosphoramidon. In the presence of both of DFP and phosphoramidon, degradation of BK was inhibited, whereas captopril had no effect on the degradation of BK. These results demonstrate that major kininases in rat urine are neutral endopeptidase and carboXypeptidase Y-like exopeptidase.

Enhancement of relaxor properties by Nb doping in Ba0.8Sr0.12Ca0.08TiO3 lead-free ferroelectric ceramics

“…According to the aforementioned results (Section I.B.4), the major kininases in urine collected from the rat ureter are CPY-like endopeptidase and NEP (Kuribayashi et al, 1993). In human urine, these two peptidases are also major kininases, but the contribution of kininases is dependent on the pH of the urine; therefore, NEP is more active at a neutral pH, whereas CPY is active at both neutral and acidic pH values, as demonstrated by the effects of inhibitors on each enzyme (Saito et al, 1996).…”

A Missing Link Between a High Salt Intake and Blood Pressure Increase

“…A microdissection technique performed in the individual nephrons revealed that kininase activity is present not only in the proximal tubules, but also in the medullary CD (108). We identified carboxypeptidase Y-like exopeptidase (CPY) and neutral endopeptidase (NEP) as major kininases in rat urine (110). Carboxypeptidase Y was originally found in yeast.…”

Diuretic and Natriuretic Effect of Ebelactone B in Anesthetized Rats by Inhibition of a Urinary Carboxypeptidase Y-Like Kininase.

“…This suggests that EB is a candidate for a new type of diuretic and natriuretic agent. NEP and CPY-like exopeptidase in rat urine were sepa rated by using a Superdex 200 column as described in the previous paper (3). Plasma samples were prepared from blood collected from the carotid artery under ether anesthesia (2).…”

“…Enzyme activities of isolated CPA, CPB and CPY were determined with peptide substrates: Z-Gly Phe for CPA (5), Bz-Gly-Arg for CPB (6) and Z-Phe-Leu for CPY (7). Assays of kininase activity and detection of BK fragments were carried out by HPLC (2,3). The in vivo effects of EB were studied in male Sprague-Dawley strain rats (SPF, 280-350g, 8 to 10-week-old, anesthetized with sodium pentobarbital, 40 mg/kg, i.p.).…”