• Analytical Science and Technology
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• v.8 no.3
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• pp.359-364
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• 1995

Urinary dipeptidase(Udpase) was assayed by fluorometric analysis of NADH which was produced from an indicator enzyme, L-alanine dehydrogenase. The reaction mixture was consisted of a dipeptide(L-ala-L-ala), ${\beta}-NAD^+$, L-alanine dehydrogenase in 12.5 mM sodium carbonate buffer, pH 9.0, and urinary dipeptidase which initiated the reaction. The fluorescence intensity of NADH was measured as a function of time with the excitation wavelength at 340nm and emission at 460nm. Comparison of this fluorometric method with the conventional spectrophotometric method utilizing glycyldehydrophenylalanine(Gdp) as substrate provided the correlation coefficient of 0.996 and increased the sensitivity more than ten times.

• 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.

• 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.