Purification and characterization of dipeptidyl peptidase IV-like enzymes from bovine testes.
Until now, only recombinant forms of dipeptidyl peptidase (DPP) 8 and 9 have been characterized. We purified non DPPII-non DPPIV enzymes from a natural source. A first DPP8/9-like enzyme was enriched 1160-fold from bovine testes and identified as 'DPP9-like enzyme' by using an anti-DPP9 antibody. A second 576-fold enriched preparation ('DPP enriched peak 3') also showed DPP8/9-like activity. SDS-PAGE analysis showed that the DPP9-like enzyme had a monomeric molecular mass of approx. 100 kDa. Size exclusion chromatography generated a native molecular mass of 164 kDa for the DPP9-like enzyme and one of 234 kDa for the DPP enriched peak 3, suggesting that both proteins appeared to be dimeric. Both enriched preparations and rDPP8 showed roughly similar substrate specificity and inhibitor profiles. The DPP9-like enzyme and the DPP enriched peak 3 possessed a neutral pH optimum and were stable at -80 degrees C. We can conclude that the natural DPP9-like enzyme and the DPP enriched peak 3 are closely related to the recombinant forms of human DPP9 and DPP8.
Laboratory of Medical Biochemistry, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium.
Veronique
V
Dubois
Anne-Marie
AM
Lambeir
Pieter
P
Van der Veken
Koen
K
Augustyns
John
J
Creemers
Xin
X
Chen
Simon
S
Scharpé
Ingrid
I
De Meester
D000818:Animals; D002417:Cattle; D002850:Chromatography, Gel; D018819:Dipeptidyl Peptidase 4 / Q000302:isolation & purification* / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D008297:Male; D008970:Molecular Weight; D013379:Substrate Specificity; D013737:Testis / Q000201:enzymology*
D018819:Dipeptidyl Peptidase 4