TY - JOUR
T1 - Studies on trypsin activation of inactive renin in rat plasma
AU - Glorioso, N.
AU - Madeddu, P.
AU - Dessi-Fulgheri, P.
AU - Anania, V.
AU - Meloni, F.
AU - Fois, G.
AU - Bandiera, F.
AU - Rappelli, A.
PY - 1982
Y1 - 1982
N2 - The experimental conditions of trypsin activation of inactive renin in rat plasma have been studied. Our results showed that the pH optimum of trypsin-activated renin is 6.2, the same as that of rat plasma active renin. Trypsin concentration and incubation time might also interfere with the activation process. Trypsin concentration below 2 mg/ml cannot activate inactive renin. Trypsin at a concentration of 6 mg/ml for 1 min. can cleave dialyzable fragments from renin substrate which can generate Angiotensin I at 37°C with a pH optimum of 5.3 but which do not affect Angiotensin generation at pH 6.2. Longer incubations (more than 2 min.), on the contrary, can produce a cleavage at 4°C of Angiotensin I containing fragments directly from renin substrate strongly interfering with measurements of renin activity at pH 6.2. Trypsin concentrations lower than endogenous rat plasma anti-trypsin activity do not activate inactive renin. Much higher concentrations of trypsin, however, are needed to obtain optimum activation of inactive renin. in average, 40% of the total circulating renin in rat plasma can be activated by trypsin.
AB - The experimental conditions of trypsin activation of inactive renin in rat plasma have been studied. Our results showed that the pH optimum of trypsin-activated renin is 6.2, the same as that of rat plasma active renin. Trypsin concentration and incubation time might also interfere with the activation process. Trypsin concentration below 2 mg/ml cannot activate inactive renin. Trypsin at a concentration of 6 mg/ml for 1 min. can cleave dialyzable fragments from renin substrate which can generate Angiotensin I at 37°C with a pH optimum of 5.3 but which do not affect Angiotensin generation at pH 6.2. Longer incubations (more than 2 min.), on the contrary, can produce a cleavage at 4°C of Angiotensin I containing fragments directly from renin substrate strongly interfering with measurements of renin activity at pH 6.2. Trypsin concentrations lower than endogenous rat plasma anti-trypsin activity do not activate inactive renin. Much higher concentrations of trypsin, however, are needed to obtain optimum activation of inactive renin. in average, 40% of the total circulating renin in rat plasma can be activated by trypsin.
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U2 - 10.3109/10641968209062384
DO - 10.3109/10641968209062384
M3 - Article
C2 - 6756691
AN - SCOPUS:0020444526
VL - A4
SP - 2203
EP - 2212
JO - Clinical and Experimental Hypertension
JF - Clinical and Experimental Hypertension
SN - 1064-1963
IS - 11-12
ER -