Biomedical subjects
T Inagami
Publications and source records attributed to T Inagami.
Isolation of completely inactive plasma prorenin and its activation by kallikreins. A possible new link between renin and kallikrein.
Existing views on prorenin are conflicting and its physiological activation mechanism is not clear. In an attempt to obtain clearcut views on the molecular properties of prorenin in human plasma, the renin zymogen (prorenin) was separated from active renin by two steps of affinity chromatography and it was demonstrated that prorenin is a completely inactivate zymogen contrary to the existing information. Inactive prorenin has an apparent molecular of 56,000 contrary to 46,000-43,000 of partially active prorenin. Isolated and acid-treated human prorenin was shown to be activated by kallikreins from human urine and plasma. This activation was completely blocked by Trasylol. Hog pancreatic kallikrein also activated human prorenin. The kallikrein mediated activation of prorenin indicates the existence of a new link between the vasoconstricting renin-angiotensin system and the vasodilating kallikreinkinin system.
Specific antibody to hog renal renin and its application to the direct radioimmunoassay of renin in various organs.
We produced anti-hog renin antibodies using as antigens pure hog renal renin that either had been insolubilized or conjugated to tetanus toxoid. High titer antibodies were obtained, which demonstrated different cross-reactivity with renins from other species. A direct radioimmunoassay for renin was developed using antibody, monoiodinated 125I-hog renin, and various methods for separating free and antibody-bound trace. This assay was capable of detecting 40 pg of hog renin and was applied to the determination of renin in hog blood and other organs. Based on the direct measurement of renin by this radioimmunoassay, the renin-like activity (i.e., the ability to generate angiotensin I from renin substrate preparations) of the pituitary gland was found to be due mostly to true renin, whereas the renin activity of other hog tissues, including the adrenal gland, liver, lung, spleen, and submaxillary gland, was not identified as renin and may have been due to cathepsins.
Activity and molecular weight of renin of plasma and kidney in SHRSP [proceedings].
Explore the source record for details and available documents.
Recent development in the biochemistry of renin [proceedings].
Explore the source record for details and available documents.
Partial purification of prorenin and activation by kallikreins: a possible new link between renin and kallikrein systems.
With the objective of identifying prorenin and its physiological activation mechanism, human plasma prorenin was completely separated from active renin for the first time. It was shown that prorenin has no activity whereas active renin has no potential for further activation. Urinary kallikreins were found to activate prorenin fractions freed from kallikrein inhibitors by affinity chromatography and treatment at pH 3.3. Human plasma kallikrein also exhibited weak activation.
Isolation and characterization of renin and high molecular weight forms of renin from various species.
Explore the source record for details and available documents.
Rat renin: purification and characterization.
In order to clarify the molecular basis of the unique features of rat renin (EC 3.4.99.19) and to provide materials and basic information for high blood pressure studies in rats, renin was purified from rat kidney. The final step of purification on CM-cellulose separated renin into three major isoenzyme peaks, R-I, R-II, R-III, and an additional minor peak. These preparations were judged homogeneous by multiple criteria, and the isoenzymes were found to have similar amino acid compositions. The amino acid composition is also closely analogous to hog renin, except that rat renin has a higher cysteine content. In contrast to hog renin, the rat enzymes do not contain amino sugars, yet are apparently glycoproteins as judged by their affinity for concanavalin A. The molecular weights of R-I, R-II, and R-III were estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis to be 37 000, 36 000 and 35 000, respectively. The isoelectric points were 5.05, 5.15 and 5.22, respectively. The specific activities of the purified enzymes (determined using rat plasma as substrate) were 615, 626 and 452 Goldblatt units/mg, respectively. Comparison of activities with the hog- and rat-derived substrates indicated a preference for that from the rat. The reaction of the rat enzymes with a synthetic peptide substrate had a similar catalytic rate constant to the hog enzyme, indicating close similarity in the active site region of the two enzymes.
Immunochemical identification of renin in rat brain and distinction from acid proteases.
Explore the source record for details and available documents.
Purification of human renin.
Explore the source record for details and available documents.
Definitive evidence for renin in rat brain by affinity chromatographic separation from protease.
1. Angiotensin I-generating activity of rat brain extract was separated into two components by affinity chromatography on a casein-Sepharose gel column. 2. The component without affinity to the gel was identified as true renin on the basis of its sensitivity to anti-renin antibody and the lack of protease activity. 3. The second renin-like component with affinity to the gel was a protease insensitive to the anti-renin antibody. Its renin-like activity examined with sheep substrate was pronounced compared with the rate of angiotensin I generation from the rat substrate. 4. It was concluded that rat brain contains true renin, which can be detected by the use of rat substrate but can be masked when examined with sheep substrate.
Tissue edema and arterial lesions produced by pure submaxillary gland renin of mouse.
In order to identify the nature of the substance(s) that causes pancreatic edema, pleural effusion, hematolcrit increase, and vascular lesion upon administration of renal extracts, effects of a pure preparation of submaxillary gland renin of mouse on blood vessels were studied. This enzyme was administered intraperitoneally to conscious anehpric rats. Blood pressure elevation recorded under unrestricted conditions was proportional to pancreatic edema, pleural effusion, hematocrit increase, and vascular lesions in small arteries and arterioles. Since the renin administered does not contain any substances and since the function of this enzyme is quite analogous to renal renin, these results have been interpreted to indicate that renin possesses both pressor and permeability activities and that the action of renin alone can account for the vascular lesions and the increased vascular permeability.
Native form of renin in the kidney.
Renin (EC 3.4.99.19) has been observed to exist in a high molecular weight (Mr greater than 50,000) and a low molecular weight from (Mr approximately 42,000) in various tissues. Little is known concerning the origin and function of the high molecular weight form of renin and its relationship to low molecular weight renin. We have found that the high molecular weight form of renin in the kidney was converted to the low molecular weight form during the extraction process. The conversion is apparenly catalyzed by an agent(s) which requires free sulfhydryl groups since blockers of sulfhydryl groups completely suppress the conversion. This conversion could not be prevented by various specific inhibitors of serine proteases nor by the metal chelator EDTA. By the use of Na-tetrathionate it was possible to preserve the renin activity of hog kidney exclusively in the high molecular weight form. Similarly, using N-ethylmaleimide it was shown that a similar high molecular weight form of renin is the exclusive form present in rat kidney. These results suggest that the high molecular weight form of renin is the native form stored in the kidney and that it is converted by an enzyme or agent requiring sulfhydryl groups to the circulating (low molecular weight) form when it is secreted into blood. Renin activity was increased to approximately 155% of the original level upon conversion.
Pure Renin. Isolation from hog kidney and characterization.
The pressor enzyme renin (EC 3.4.99.19) was isolated in a pure and stable form from hog kidney by affinity chromatography on a pepstatin/agarose gel followed by three additional steps of conventional chromatography. Destruction of the enzyme by proteolysis during isolation was prevented by chemically eliminating proteases in extracts. The pure preparation was used for the characterization of this enzyme. Renin was found to be a glycoprotein containing glucosamine and possessing binding affinity to concanavalin A. Contrary to previous reports, pure renin is stable at neutral pH either at 4 or -20 degrees for 3 to 8 weeks. It has a molecular weight of 36,400 as determined by equilibrium ultracentrifugation, an isoelectric point of 5.2 and E1%1cm (280 nm) of 9.1. In contrast to crude preparations, the enzyme activity has a broad pH optimum between pH 5.5 and 7.0 for both hog angiotensinogen and the synthetic octapeptide substrate benzyloxycarbonyl-Pro-Phe-His-Leu-Leu-Val-Tyr-Ser-beta-naphthylamide. The rate of formation of angiotensin I from hog angiotensinogen at pH 6.0 and 37 degrees was 267 microng/h/microng of renin, or 2000 Goldblatt units/mg of renin. For the synthetic fluorogenic octapeptide substrate benzyloxycarbonyl-Pro-Phe-His-Leu-Leu-Val-Tyr-Ser-beta-naphthylamide, a Km of 33 micronM and a Vmax of 0.94 micronmol/h/mg of enzyme were obtained at pH 6.5 and 37 degrees.
Renin and precursors : purification, characterization and activation mechanism (author's transl).
Explore the source record for details and available documents.
Renin and precursors: purification, characterization, and studies on active site.
Explore the source record for details and available documents.
Prostaglandins and renin release: I. Stimulation of renin release from rabbit renal cortical slices by PGI2.
Prostaglandins have been shown to be involved in the mechanism of renin secretion in a variety of situations. Both arachidonic acid and prostaglandin endoperoxide have been shown to release renin from cortical slices and to be converted to PGI2 by cortical microsomes. In the present studies PGI2 was found to cause a time dependent increase in renin release from rabbit renal cortical slices, a system isolated from any indirect effects that result from the administration of prostaglandins in vivo. The stimulation was linear up to 30 minutes and effective over a range of concentrations from 10(7 M to 10(-5) M. At similar concentrations 6-keto-prostaglandin F1alpha was not active on these slices. Thus, it is proposed that PGI2 exerts a direct effect on the release of renin from cortical cells and may be the mediator of arachidonate or prostaglandin endoperoxide stimulated renin secretion.