Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.4.21.4 (trypsin)
42,187 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Rat renal lymph contains 254 +/- 17 ng/ml (means +/- SEM, N = 20) of immunoreactive glandular kallikrein. Like the immunoreactive glandular kallikrein in plasma, it is biologically inactive. Gel filtration of renal lymph reveals profiles for immunoreactive glandular kallikrein, protein, and inhibition of trypsin and kallikrein which resemble those seen for plasma except that high molecular weight plasma components are reduced or missing in renal lymph. In contrast, gel filtration of thoracic lymph reveals immunoreactive glandular kallikrein and protein profiles which are indistinguishable from those seen with plasma. Renin levels are 170-fold higher in renal lymph than in thoracic lymph while angiotensin-converting enzyme levels are only 16% those of thoracic lymph. In keeping with the high renin and low converting enzyme activities, renal lymph contains high levels of angiotensin I. Immunoreactive glandular kallikrein levels in renal lymph, thoracic lymph and plasma do not show the striking differences observed for renin.
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PMID:Kallikrein-kinin and renin-angiotensin systems in rat renal lymph. 608 86

Cell suspensions were prepared from rat renal cortical tissue by dispersion with 0.1% collagenase. Unit gravity sedimentation in a 1%-4% Ficoll gradient resulted in a single-cell suspension enriched in juxtaglomerular (JG) cells. Both the cellular renin activity and the amount of renin released into the supernatant increased with time when the suspensions were incubated for 1 hour at 37 degrees C in tissue culture medium. These cells responded to epinephrine and norepinephrine by increasing both synthesis and release of renin. The response was blocked by timolol but not by phenoxybenzamine. Cell suspensions prepared in the same manner but using 0.25% trypsin as the dispersing enzyme neither synthesized nor released renin into the tissue culture medium when similarly incubated. Trypsin-dispersed cells did not respond to catecholamine stimulation. Renin synthesis and release in collagenase-dispersed JG cells were unaltered by changes in Na, K, or Ca ion concentrations. Angiotensin II inhibited release, while saline extracts of clipped kidney from renal hypertensive rats stimulated renin release by these cells.
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PMID:Responses of juxtaglomerular cell suspensions to various stimuli. 626 Jun 44

Cells of the homogeneous hybrid line neuroblastoma x glioma (NG108-15) have many neuronal properties. Immunocytochemical tests show that they contain both immunoreactive renin and angiotensin; direct radioimmunoassays show that they are positive for renin, angiotensin I, and angiotensin II; enzymatic assays show that they contain angiotensinogen and converting enzyme as well. The renin appears to be present in an enzymatically inactive form that can be activated by trypsin and then blocked by antiserum to purified mouse submaxillary renin. Renin concentration and activity are increased by enhancing cellular differentiation with dibutyryl cyclic adenosine monophosphate or by serum withdrawal. These findings demonstrate a complete renin-angiotensin system within these neuron-like cells, and suggest that activation of intracellular renin could generate angiotensin II.
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PMID:Renin and angiotensin: the complete system within the neuroblastoma x glioma cell. 627 92

Renin biosynthesis was studied in a juxtaglomerular cell tumor. The tumoral tissue had a high renin content (180 Goldblatt Units/g of tissue), was heavily stained by immunofluorescence using human renin antiserum, and exhibited numerous characteristic secretory granules by electron microscopy. In one series of experiments, renin biosynthesis was studied in tissue slices, by following the incorporation of radiolabeled amino acids into specific immunoprecipitable renin. Time course studies showed that renin was first synthesized in a high molecular weight form, 55,000 mol wt, i.e., 10,000 mol wt higher than that of active renin, and was then converted into a 44,000-mol wt form. In a second series of experiments renin tumoral cells were cultured. Small, round, birefringent cells obtained after collagenase digestion produced renin in both primary culture and subculture media. After 5 d most of the renin found in the culture medium was inactive, but could be activated by trypsin treatment. The tumoral tissue exhibited a strong renin immunofluorescence and numerous secretory granules were observed by electron microscopy. In contrast, the renin-producing cells isolated from this tumor and grown in culture showed little renin immunofluorescence and no secretory granule could be observed. The renin-producing cells in primary culture and subculture were pulsed with radiolabeled amino acids, and immunoprecipitable radiolabeled renin was found in the culture media, thus demonstrating the actual biosynthesis of the enzyme. This renin was not stored inside cultured cells but was rapidly released into the medium and had a molecular weight of 55,000. No conversion of this inactive high molecular weight renin into the active, 44,000 mol wt form of renin was observed. We postulate the existence of two pathways for the processing, packaging, and secretion of renin in the tumoral cells: in juxtaglomerular cells of tumoral tissue renin is synthesized as a preprorenin and rapidly converted into prorenin (55,000 mol wt), which is in turn packaged in secretory granules where it is processed into active renin (44,000 mol wt) and finally secreted; in the cultured tumoral cells renin is still biosynthesized as a preprorenin molecule and then converted into prorenin, but is neither stored as granules nor processed into active renin. In this case the renin is released in an inactive form.
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PMID:Renin biosynthesis by human tumoral juxtaglomerular cells. Evidences for a renin precursor. 632 35

To determine the structural basis for the highly specific action of renin, structural features of the active site and the complete amino acid sequence of mouse submaxillary gland renin were determined. A rapid method was developed for a large scale purification of renin from mouse submaxillary gland. The active site of renin was shown to consist of 2 aspartyl residues, 2 tyrosyl residues and one arginyl residue, the structures analogous to the active site of pepsin and other acid proteases. Renin was found to consist of one heavy chain (Mr = 31,036) and one light chain (Mr = 5,458) connected by a disulfide bridge. Amino acid sequences of these chains were determined using overlapping peptides generated by cleavage with cyanogen bromide, trypsin, Staphylococcus aureus protease and Lysobacter enzymogenes endoproteinase Lys-C. Sequences involving 2 catalytically essential aspartyl residues 32 and 215, characteristic to acid proteases, were found identical with pepsin, penicillopepsin and chymosin. The sequence of L-chain was homologous with carboxyl terminal region of porcine pepsin in 46% of amino acid residues. H-chain showed 41% homology with 284 residues on the amino-terminal side of the porcine pepsin molecule. Residues identical in renin and acid proteases are distributed throughout the length of the molecules, suggesting a similarity in their overall structure.
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PMID:Structure of mouse submaxillary gland renin. 635 66

We developed new sensitive direct radioimmunoassay for human plasma renin. Renin was purified from Haas' preparation utilizing a pepstatin-C6-Sepharose affinity chromatography. Antiserum, prepared by immunizing rabbits with the purified renin, was used for the direct radioimmunoassay at a final dilution of 1:30,000. The antibody was specific for human renal and plasma renin, but did not cross-react with cathepsin D, trypsin, or renins of mouse, dog, and rat. Radioimmunoassay was performed by the double antibody technique using the delayed tracer addition method. In this method, a standard curve was obtained over a range from 0.2 to 8.0 ng/ml. The values from our assay correlated well with total renin activity measured as the generation rate of angiotensin I after trypsin activation (r = 0.78, p less than 0.01), but correlated weakly with active renin activity. This finding disclosed that both active and inactive renin were detected by this method. In normal participants, plasma renin concentration determined by direct radioimmunoassay was increased by standing and furosemide injection. The plasma renin concentration determined by direct radioimmunoassay of patients with essential hypertension (0.7 to 1.7 ng/ml) was not significantly different from values in normal controls (0.8 to 1.9 ng/ml). The values were higher in patients with renovascular hypertension (1.6 to 2.7 ng/ml), malignant hypertension (2.8 to 3.4 ng/ml) and Bartter's syndrome (1.8 to 2.5 ng/ml), but lower in patients with primary aldosteronism (0.4 to 0.8 ng/ml) than in normal controls. This newly developed radioimmunoassay for human renin was sensitive enough to estimate the levels of renin in plasma of patients with low renin hypertension. It provides a new tool for the understanding of the renin-angiotensin system under various clinical conditions.
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PMID:A new sensitive direct radioimmunoassay for human plasma renin and its clinical application. 638 35

Human DNA coding for renin was identified and sequenced. The gene consisted of 10 exons corresponding to a 1500 nucleotide mRNA was broken up by long stretches of 'nonsense' DNA (introns) and spanned 12,000 base pairs. In addition, the sequence of nucleotides involved in regulation of the gene was determined by sequencing upstream. Prediction of the amino acid sequence of human preprorenin revealed likely sites of processing. This helps explain many past experimental observations. For example, the pro region contained adjacent likely cleavage sites for trypsin and pepsin and so reveals why both trypsin and pepsin can activate prorenin. The structure of human renin had features involved in its highly specific hydrolysis of the Leu10-Val11 bond unique to human angiotensinogen: in particular leucine 224 (instead of valine). Renin gene expression was studied in the mouse by quantification of both renin activity and its mRNA. Sodium depletion, captopril and spironolactone increased expression of Ren-1 in the kidney. The unusual, duplicated, mouse gene, Ren-2, which is expressed in the submandibular gland was, regulated by (dihydro)testosterone in male mice and by thyroid hormone in female mice.
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PMID:Human renin gene sequence, gene regulation and prorenin processing. 640 Mar 69

A sensitive direct human renin radio-immunoassay has been developed for clinical use. The antigen source was human renal renin purified from Haas' preparation by pepstatin-C6-sepharose affinity chromatography, this was used to prepare a specific human renin antibody. The radio-immunoassay was performed by the double antibody technique using the delayed tracer addition method. Standard curves were obtained over the range 0.2-8.0 ng/ml. Dilution curves of human renal renin and human plasma were superimposable on the standard curve. Both active and inactive renin were detected by this method, and measurements correlated well with total renin activity after trypsin activation. Intra- and inter-assay coefficients of variance were 4.6% and 5.1%, respectively. Renin concentration was higher in patients with renovascular hypertension (1.97 +/- 0.38 ng/ml, mean +/- s.d., n = 10, P less than 0.01), but lower in primary aldosteronism (0.66 +/- 0.16 ng/ml, n = 13, P less than 0.01) compared with essential hypertension (1.38 +/- 0.34 ng/ml, n = 12). This method provides a new tool for the investigation of the renin-angiotensin system in man.
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PMID:Sensitive direct radio-immunoassay for human renin. 640 Mar 70

Amnion and chorion cells from human fetal membranes have been cultured. Chorionic cells secrete renin whereas amnionic cells do not. Renin is secreted by chorionic cells as an inactive form that can be activated by trypsin treatment or acid dialysis. The antigenic and enzymatic properties of activated chorionic renin and kidney renin are similar. Incorporation of [35S]methionine in the culture demonstrates that chorionic renin is secreted as a high molecular weight form, 54K. This 54K inactive renin could represent the proenzyme.
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PMID:Human chorionic cells in primary culture: a model for renin biosynthesis. 674 79

Human chorio-amnion from term pregnancy was perfused in vitro in a dual perfusion apparatus. Renin released from the fetal membranes was almost entirely in the form of inactive renin (IR) (trypsin-activated). IR was released from both the chorion side and the amnion side. IR introduced on the chorion side of the chorio-amnion did not appear on the amnion side. When cells isolated from term amnion and chorion were grown in tissue culture, IR was released continuously from chorionic cells but not from amnionic cells. The release of IR did not parallel the release of LDH from cultured chorion cells. Exposure to low calcium medium (with or without EGTA) decreased IR release while LDH release increased (or remained constant). Exposure to the calcium ionophore (A 23187) resulted in a marked decrease in IR release. The release of IR from chorionic cells shows some similarities to the release of HCG from trophoblasts. It is expected that IR release from the chorion will show some similarities to R release from the kidney as well as major differences. The function, regulation, and processing of chorionic IR remain to be elucidated.
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PMID:Release of inactive renin from human fetal membranes and isolated trophoblasts. 675 76


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