Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.21.4 (trypsin)
 42,187 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. Complementing the work of Gervitz R. K., Hiraichi E., Fichman M. and Lavras A. A. C. Comp. Biochem. Physiol. 86A, 503-507 (1987), conditions have been established for measuring plasma renin activity (PRA) of the venomous snake Bothrops jararaca (Bj). 2. It corresponded to 115.9 +/- 11.5 ng equivalents of angiotensin II (AII) per ml of plasma (N = 13). 3. PRA did not increase when Bj plasma was submitted to acid-cryo-trypsin Bitis arietans venom activation of inactive renin. 4. This may indicate either absence of inactive renin in this plasma or lack of its activation, due to the already demonstrated (Nahas L., Kamiguti A. S., Betti F., Martins I. S. S. and Rodrigues M. I., Comp. Biochem. Physiol. 69A, 739-743, 1981; Prezoto B. C., Hiraichi E., Abdalla F. M. F. and Picarelli Z. P., Comp. Biochem. Physiol. 99C, 135-139, 1991) absence of factor XII.
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PMID:Active and inactive renin in the plasma of the snake Bothrops jararaca. 135 20

To investigate the effects of age and posture on plasma active and inactive renin, we measured the plasma active renin concentration (ARC) and inactive renin concentration (IRC) in 81 healthy subjects. The subjects were divided into five groups according to age and body position at the time the blood was taken. Group I included 15 five-day-old newborns in a supine position. Group H included 18 adults, aged from 20 to 50 years, who were in a supine position. Group III included 21 adults, over 50 years old, who were in a supine position. Group IV included 20 adults, aged from 20 to 50 years, who were in an upright position. Group V included 19 adults, over 50 years old, who were in an upright position. Twelve subjects were included in Groups II and IV. Plasma active renin was measured by the amount of angiotensin I general when an exogenous renin substrate was added. Plasma inactive renin was activated by trypsin. The results showed that, in a supine position, both ARC and IRC were significantly higher in newborns (Group I) than in the two adult groups (Groups II and III). The mean of the ARC/TPRC (total plasma renin concentration) ratio was lower in adults over 50 years old (Group III) than in those from 20 to 50 years old (Group II), but the difference was not statistically significant.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effects of age and posture on plasma active renin and plasma inactive renin in normal subjects. 135 17

To investigate plasma renin and prorenin levels in non-insulin-dependent diabetes mellitus (NIDDM) and their relation with autonomic nervous function and renal impairment, we measured plasma renin and prorenin levels in 39 NIDDM patients. The patients included 21 males and 18 females, aged 56.3 +/- 6.2. Thirty-four normal age-matched subjects served as controls. Autonomic nervous function was evaluated in 23 patients by the performance of cardiovascular reflex tests. The plasma renin concentration was measured by angiotensin I generation after the addition of an exogenous substrate. Plasma prorenin was activated by trypsin. The results showed that the plasma renin concentration was similar between NIDDM patients and normal subjects, while plasma prorenin was higher in NIDDM patients. No correlation existed between the plasma renin or prorenin levels and autonomic nervous function. The patients with abnormally high levels of prorenin also had a similarly high plasma renin level but not a high creatinine clearance (Ccr) or daily proteinuria. The plasma renin level was correlated inversely with daily proteinuria but not with Ccr. These results suggest that the high plasma prorenin levels in some diabetic patients cannot be explained by renal impairment, poor prorenin conversion or autonomic dysfunction. The hyporeninemia in some patients may be related to microvascular involvement of the kidney.
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PMID:Plasma prorenin and renin levels in non-insulin-dependent diabetes mellitus. 136 16

This study was undertaken 1) to determine whether or not renin is present in synovial fluid in patients with rheumatoid arthritis and osteoarthritis, and, if present, 2) to investigate whether it is synthesized in synovial fluid, or it is only transported from the circulation into the synovial cavity. The active renin concentration (indirect) was measured with angiotensin I radioimmunoassay kits. Inactive renin was converted into active renin with Sepharose-bound trypsin. Both active and inactive forms of renin were found in synovial fluid. They were significantly higher in patients with rheumatoid arthritis (n = 9) than in those with osteoarthritis (n = 16). In plasma, the concentration of inactive renin was significantly higher (P less than 0.001) in the former. Albumin, transferrin, alpha 2-macroglobulin, ceruloplasmin and immunoglobulins G and M were also found in synovial fluid. In each disease, a plot of the log ratio of synovial fluid to the serum concentration against the log molecular weight of each protein gave an approximately straight line curve, suggesting that these proteins are derived from the circulation and are transported into the synovial cavity. In contrast, the ratio of synovial fluid to plasma concentrations of active renin was significantly higher than that predicted on the basis of the above-mentioned interrelationships in both diseases, whereas the ratio of inactive renin was significantly lower. These findings suggest that 1) inactive and active renin are filtered into the synovial fluid from the circulation, and that 2) inactive renin is converted into the active form in the fluid.
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PMID:Prorenin-renin axis in synovial fluid in patients with rheumatoid arthritis and osteoarthritis. 138 4

Human arterial tissue was shown to have renin-like activity. For its determination the authors propose methodological approaches. The optimum pH of renin activity in the vascular wall was found to be 5.8-6.0. The renin-like enzyme was ascertained to be present in the vascular wall as inactive and to be activated by trypsin. The renin activity was compared in the human vascular wall and human plasma. Their optimum pHs were nearly identical. The methodological features determined in this paper allowed one to differentiate the true renin-like activity from the activity of acid proteases.
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PMID:[Methodologic features of determining renin-like activity in human arteries]. 140 53

The effects of graded exercise on plasma concentrations of active and inactive renin were studied in seven healthy men. Exercise was performed on a cycle ergometer at four different exercise intensities (corresponding to 30%, 50%, 80% and 87% of VO2max) for 10 min each. Concentrations of active renin and total renin after activation by trypsin were measured by direct immunoradiometric assay. Non-trypsin-activated renin concentration (inactive) was obtained by subtraction. Active renin concentrations at 30%, 50%, 80% and 87% of VO2max were 1.2, 1.9, 3.1 and 4.6 times higher than the control concentration, respectively. Similar increases in plasma renin concentration, determined by conventional enzymatic assay, were observed at every stage. In contrast, changes in inactive renin concentration were not significant at any stage. Significant increases in noradrenaline concentration were found at every exercise stage, but adrenaline, aldosterone and lactate concentrations were significantly elevated only after exercise at 50%, 80% and 87% of VO2max. The similarity between the changes in concentration of active renin and noradrenaline would suggest that sympathetic nerve activity may have been responsible either for the release of active renin or for the conversion of inactive renin to its active form in the kidney.
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PMID:Active and inactive renin after exercise. 142 33

In humans, active renin is generated by the removal of a 43-amino acid prosegment from the zymogen prorenin. This cleavage event is highly specific, occurring at only one of the seven pairs of basic amino acids in the body of preprorenin. This cleavage site selectivity is also displayed by a number of other proteases in vitro and in mouse pituitary AtT-20 cells transfected with a human preprorenin expression vector, suggesting that specificity of cleavage is directed in part by the primary sequence, the higher order structure, or both of prorenin itself. To test this hypothesis, single amino acid mutations were introduced in the region of human preprorenin surrounding the natural cleavage site, and the resultant recombinant proteins were expressed in cultured Chinese hamster ovary and AtT-20 cells. The results suggest that amino acids in addition to the pair of basic amino acids surrounding the cleavage site affect the ability of both trypsin and the endogenous AtT-20 processing enzyme to cleave prorenin. Notably, although a proline at position -4 is essential for processing of prorenin in AtT-20 cells and is correlated with predicted formation of a beta-turn at this position, site-directed mutations suggest that this structural feature in addition to a pair of basic amino acids is not sufficient to lead to proteolytic activation of prorenin. Displacement of sequences surrounding the cleavage site to a position 10 amino acids toward the amino terminus led to partial processing of a mutated prorenin.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Molecular determinants of human prorenin processing. 145 93

1. In previous studies we have demonstrated and solved several methodological problems in relation to the measurement of prorenin by trypsin activation in rat, bovine, hog and horse plasma. 2. The aim of the present study was to develop a method for the measurement of prorenin in bovine and porcine ovarian follicular fluid. 3. Trypsin activation of follicular fluid generated angiotensin I immunoreactive material (AI IM) in both species. 4. The AI IM interfered with the renin assay, but could be completely removed by a cation exchange resin in a batch-wise technique. 5. The enzymatic activity of trypsin-activated prorenin and pre-existing active renin was completely inhibited by a specific inhibitor of renin. 6. The reactions were optimized and an accurate measurement of prorenin in ovarian follicular fluid was developed. 7. The existence of prorenin and renin in bovine ovarian follicular fluid was established. Prorenin and renin in porcine ovarian follicular fluid was demonstrated for the first time. 8. The ratio between ovarian follicular fluid and plasma was 43 for prorenin and 19 for active renin in cattle. The same ratios in pigs were 1.3 and 0.4, respectively. These findings indicate a species difference with respect to the amount of prorenin or active renin present in ovarian follicular fluid.
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PMID:Measurement and identification of prorenin and renin in ovarian follicular fluid from cattle and pig. 151 75

We have identified and characterized an anti-human renin monoclonal antibody R1-20-5 that is selective for human active renin. R1-20-5 binds active renin with a dissociation constant (Kd) of 2.5 x 10(-7) M/l and inhibits renin enzymatic activity with an inhibitory constant (IC50) of 1.4 x 10(-8) M/l. R1-20-5 competes with a synthetic renin inhibitor for binding with renin, demonstrating further that it is binding to or close to the active site. This antibody does not bind prorenin in human plasma or recombinant prorenin expressed by L-929 fibroblasts transfected with human renin gene. Furthermore, trypsin activation of prorenin resulted in immunoreactivity of the activated prorenin toward the antibody. In addition, an immunoaffinity column of R1-20-5 coupled to Sepharose retained active renin but had a low affinity for prorenin. A sensitive and rapid solid phase radioimmunoassay for active renin was developed using a "sandwich" technique employing R1-20-5 and a second non-active site-directed monoclonal antibody to human renin. Renin levels in human plasma samples were determined by the standard enzymatic assay, and by the direct radioimmunoassay for active renin, before and after trypsin activation. Trypsin treatment of plasma resulted in parallel increases in both the plasma renin enzymatic activity and in the plasma active renin concentration as measured by the direct radioimmunoassay. Overall, plasma immunoreactive active renin concentration correlated significantly with plasma renin enzymatic activity (r = 0.96, p less than 0.001). In summary, the monoclonal antibody R1-20-5 is selective for human active renin and should be a very useful tool for studies of the active enzyme in humans.
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PMID:Characterization of a monoclonal antibody specific for human active renin. 154 51

Rat renin cDNA was transfected into COS-7 and Chinese hamster ovary (CHO) cells and expressed under the control of the Simian Virus 40 early promoter. Conditioned media of the transfected cells showed renin activity only after trypsin treatment, suggesting prorenin was secreted into the medium. From the trypsinized serum-free culture of the transfected CHO cells active renin was purified to homogeneity by a simple three-step procedure. The active renin had similar specific activity, molecular weight, Km, pH optimum, and isoelectric point compared to native renin. The amino-terminal sequence was the same as that deduced from the renin cDNA. This suggests that the recombinant rat renin is similar to kidney renin in many respects, and is easily obtained by the present procedures.
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PMID:Expression of rat renin in mammalian cells and its purification. 160 Jun 38


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