Hydrolysis and transport of proline-containing peptides in renal brush-border membrane vesicles from dipeptidyl peptidase IV-positive and dipeptidyl peptidase IV-negative rat strains.
In this investigation, we have demonstrated that the renal brush-border membrane of Fischer 344 rats from the Japanese Charles River Inc. specifically lacks dipeptidyl peptidase IV (DPP IV) activity, whereas the renal brush-border membrane of Fischer 344 rats from three different sources within the United States possesses normal levels of DPP IV activity. Comparison of the brush-border proteins between Charles River (U.S.A.) Fischer 344 rats (DPP IV positive) and Japanese Charles River Fischer 344 rats (DPP IV negative) revealed that a protein band (Mr = 100,000), apparently identical with DPP IV, was absent in the membranes from Japanese Charles River Fischer 344 rats. We examined the handling of radiolabeled beta-casomorphin fragment 1-5 (Tyr-Pro-[3H]Phe-Pro-Gly), a specific substrate for DPP IV, in renal brush-border membrane vesicles isolated from DPP IV-positive and DPP IV-negative rats. Although the membrane vesicles from DPP IV-positive rats were able to hydrolyze the pentapeptide to di- and tripeptides with the subsequent active transport of these products via the H+ gradient-dependent peptide transport system, the membrane vesicles from DPP IV-negative rats failed to hydrolyze the pentapeptide and hence lacked the ability to transport the radiolabel actively from the parent peptide. The H+ gradient-dependent glycyl-sarcosine uptake and the Na+ gradient-dependent proline uptake, however, were normal in DPP IV-negative rats. Urine analysis revealed that the DPP IV-negative rats excreted proline- and hydroxyproline-containing peptides in significantly increased amounts in their urine compared with control rats. Furthermore, following intravenous administration of Tyr-Pro-Phe-Pro-NH2, a peptide that is exclusively hydrolyzed by DPP IV, urinary excretion of the peptide in the intact form was many-fold greater in DPP IV-negative rats than in control rats. These data provide conclusive evidence for the obligatory role of DPP IV in the renal handling of proline (and hydroxyproline)-containing peptides.
Tiruppathi
C
C
Department of Cell and Molecular Biology, Medical College of Georgia, Augusta 30912-2100.
Miyamoto
Y
Y
Ganapathy
V
V
Roesel
R A
RA
Whitford
G M
GM
Leibach
F H
FH
D000818:Animals; D001692:Biological Transport; D002474:Cell-Free System; D018819:Dipeptidyl Peptidase 4; D004152:Dipeptidyl-Peptidases and Tripeptidyl-Peptidases / Q000378:metabolism*; D004723:Endorphins / Q000378:metabolism; D006909:Hydroxyproline / Q000378:metabolism; D066298:In Vitro Techniques; D007668:Kidney / Q000378:metabolism*; D008871:Microvilli / Q000378:metabolism; D009842:Oligopeptides / Q000378:metabolism* / Q000652:urine; D011392:Proline / Q000378:metabolism*; D051381:Rats; D011916:Rats, Inbred F344; D011922:Rats, Mutant Strains; D013329:Structure-Activity Relationship
D004723:Endorphins; D009842:Oligopeptides; C021968:beta-casomorphins; D011392:Proline; D004152:Dipeptidyl-Peptidases and Tripeptidyl-Peptidases; D018819:Dipeptidyl Peptidase 4; D006909:Hydroxyproline