• Archives of Pharmacal Research
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• v.22 no.4
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• pp.367-371
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• 1999

Effects of several durgs on rabbit renal proximal tubules were examined for the applicability of renal dipeptidase (RDPase, EC 3. 4. 13. 11) release as a model system to study nephrotoxicity. The proximal tubule prepared by the method of Taub (1990) released RDPase spontaneously in the control experiment which was confirmed by Western blotting. RDPase was also released form cisplatin, lipopolysaccardie (LPS), and indomethacin-treated tubules. Gentamicin inhibited RDPase release in a concentration-dependent manner. This RDPase release system may not be a general model to screen nephrotoxicity but could be a useful source of RDPase purification in a simple and inexpensive way.

• Archives of Pharmacal Research
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• v.16 no.4
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• pp.295-299
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• 1993

Human renal dipeptidase (RDPase) was purified from surgically removed kdneys of renal stone aptients by affinity chromatography using its specific inhibitor, cilastain, as the ligand. The partial purified RDPase of 6 mg exhivited specific activity of 99.4 unit/mg with 2, 029 fold purification. it was composed of a slow moving major band (96%) and a fast moving minor band (4%). The minor band was not a contaminant as it showed a dipeptidase-specific activity. The kinetic parameters determined with glycyldehydrophenylalanine (Gdp) as synthetic substrate were Vmax, $322.6\;\mu{mol/min/mg}$ and km, 0.120 mM. This experiment provided biochemical evidences that sugically removed, nonfunctional kidneys in respect of glomerular filtration still retained high activity of renal dipeptidase.

• Animal cells and systems
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• v.7 no.4
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• pp.309-315
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• 2003

Renal dipeptidase (RDPase, membrane dipeptidase, dehydropeptidase 1, EC 3.4.13.19) has been widely studied since it was first purified from porcine kidney brush border membrane. It was reported that RDPase activity in urine samples of acute and chronic renal failure patients decreases. Nitric oxide (NO) is a highly reactive free radical involved in a number of physiological and pathological processes. NO is able to act in a dual mode, leading either to induction of apoptosis or to blunted execution of programmed cell death. NO inhibited the RDPase release from porcine renal proximal tubules, which could be blocked by L-NAME. Chitosan, the linear polymer of D-glucosamine in $\beta$(1\longrightarrow4) linkage, not only reversed the decreased RDPase release by NO but also increased NO production in the proximal tubule cells. The stimulatory effect of NO on RDPase release from proximal tubules in the presence of chitosan must be different from the previously proposed mechanism of RDPase release via NO signaling pathway. Chitosan stimulated the RDPase release in the proximal tubules and increased RDPase activity to 220% and 250% at 0.1% and 1%, respectively. RDPase release was decreased to about 40% in the injured proximal tubules and was recovered in proportion to the increase of chitosan. Chitosan may be useful in recovery of renal function from $HgCl_2$injury.

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.319.2-319.2
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• 2002

Chitin is a major component of the shells of crustacea such as crab. shrimp and crawfish. Renal dipeptidase (RDPase. EC 3.4.13.19), an ectoenzyme of renal proximal tubules. is covalently bound to outer leaflet of lipid bilayer via glycosylphosphatidylinositol (GPI)-anchor. The biological role of RDPase was suggested as the hydrolysis of dipeptide into free-amino acids before renal reabsorption. The underlying biochemical mechanism of decreased RDPase release was suggested as nitric oxide (NO) production. (omitted)

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.7
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• pp.968-972
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• 2005

The purpose of this study was to evaluate the effects of chitosan, which is deacetylated derivative of chitin, on the renal function. Renal dipeptidase (RDPase, membrane dipeptidase, dehydropeptidase 1, EC 3.4.13.19) is glycosyl phosphatidyl-inositol (GPI)-anchored ectoenzyme of renal proximal tubular microvilli and was related with renal disease including acute renal failure, pyelitis and nephritis. The released RDPase and Udpase activities were assayed by modified fluorometric method. In vitro experimental groups were consisted of group 1, the concentration ranges of 0, 0.01, 0.05 and $0.1\%$ chitosan only, group 2, the concentration ranges of 1, 2 and 4 mM glycerol only, and group 3, the concentration ranges of 0, 0.01, 0.05 and $0.1\%$ chitosan in the presence of glycerol (4 mM). In vivo experimental groups were consisted of group 1 in which rats were treated with glycerol for the purpose of glycerol-induced renal damage, and group 2 in which rats were treated with chitosan plus glycerol. The RDPase release of 0.01, 0.05, and $0.1\%$ chitosan groups were increased in the concentration dependent manner. The RDPase release of 1, 2, and 4mM glycerol groups were decreased in the concentration dependent manner. Chitosan in the presence of glycerol restored the released RDPase activity in the proximal tubules. In vivo, chitosan inhibited the decrease of RDPase release by glycerol in the kidney and blocked the decrease of Udpase activity by glycerol in urine. These results indicated that chitosan was possible as a functional food to control renal function and its diseases.

• Archives of Pharmacal Research
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• v.25 no.1
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• pp.80-85
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• 2002

The incubation of porcine renal proximal tubules (PTs) resulted in the release of the Glycosylphosphatidylinositol (GPI)-anchored renal dipeptidase (RDPase, EC 3. 4. 13. 19) from the membrane after a lag period of approximately 6 hours. This spontaneous release of RDPase from the membrane was inhibited by antibiotics. When the incubation supernatant was added back to fresh PTs, both the antibiotic inhibition of RDPase release and the lag period disappeared. The released RDPase reacted with an anti-cross reacting determinant antibody indicating the presence of the Ins (1, 2-cyc)P. These results suggest that bacteria in the PTs, when incubated, grow find Secrete a phosphatidylinmsitol-specific phospholipase C (PIPLC). This enzyme then hydrolyses the GPI-anchored RDPase and is transferable. RDPase was purified following its release from the membrane by this simple and inexpensive method which may also be applied to other GPI-anchored proteins.

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.322.1-322.1
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• 2002

Lawsone methyl ether (LME. 2-methoxy-1, 4-naphthoquinone) is a natural compound found in balsaminaceae. In this study the effect of LME on the release of renal dipeptidase (RDPase) and alkaline phosphatase (APase) known as glycosylphosphatidylinositol (GPI) anchored proteins was examined from the renal proximal tubules. Compared with control, LME (0.5mM) increased RDPase release (218%) and APase release (135%). The increase of RDPase release by LME showed concentration-dependent effect but the release pattern of APase did not. (omitted)

• Proceedings of the PSK Conference
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• 2003.04a
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• pp.222.2-223
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• 2003

Renal dipeptidase (RDPase, EC 3.4.13.19), an ectoenzyme of renal proximal tubules, is covalently bound to outer leaflet of lipid bilayer via glycosylphosphatidylinositol (GPI)-anchor. Chitin is a major component of the shells of crustacea such as crab, shrimp and crawfish. This study was conducted to examine the effect of chitosan on RDPase release from renal proximal tubules. Nitric oxide (NO), highly reactive free radical, inhibits the release of RDPase from porcine proximal tubules. (omitted)

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.317.1-317.1
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• 2002

The action of epigallocatechin-3-gi:lllale (EGCG). polyphenol compound from green lea, on the release pattern of glycosylphosphatidylinositol (GPI)-anchored renal dipeptidase (RDPase) from renal proximal tubules (PTs) was examined. EGCG had a stronger inhibitory effect on the release of RDPase than alkaline phosphatase (APase), another GPI-anchored ectoenzyme used as a reference protein. The effect of EGCG on cell viability as assessed by MTT test was found to be intact, and moreover, was indicative of potent cell activation or proliferation. (omitted)

• Archives of Pharmacal Research
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• v.17 no.1
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• pp.21-25
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• 1994

Physico-chemical characterization of human renal dipeptidase was carried out. It was a glycoprotein with a subunit MW of approximately 47,700 dalton. The pH optimum was at 8 and its stable conformation was retained between pH 5 and 12. The kinetic parameters determined with imipenem, a noval ${\beta}-lactam$ antibiotic, were Vmax, $5.21\;\mu{mol/min/mg}$; km, 4.35 mM ; and Ki with cilastatin, $0.25\;\mu{M}$ Cilastatin demonstrated reversible competitive inhibition.