Catalytic properties of X-prolyl dipeptidyl aminopeptidase from Lactococcus lactis subsp. cremoris nTR.
An X-prolyl dipeptidyl aminopeptidase (X-PDAP; EC 3.4.14.5) was identified to be loosely bound on the inner cell membrane fraction of Lactococcus lactis subsp. cremoris nTR. The biosynthesis of X-PDAP was continuously increased before the late-log growth phase of the bacteria. Both Gly-Pro-pNA and Ala-Ala-pNA were hydrolyzed by X-PDAP; the kcat/Km value of the former was about 10-fold that of the latter. The Ki of X-Pro and Pro-X were more specific to X-PDAP than those of X-Ala. The enzyme splitting a dipeptide sequentially from beta-casomorphin as a model catalytic pattern was identified and some properties of the enzyme were further characterized.
Department of Bioengineering, Tatung Institute of Technology, Taipei, Taiwan, R.O.C.
T R
TR
Yan
S C
SC
Ho
C L
CL
Hou
D000595:Amino Acid Sequence; D018819:Dipeptidyl Peptidase 4; D004152:Dipeptidyl-Peptidases and Tripeptidyl-Peptidases / Q000378:metabolism*; D004723:Endorphins / Q000378:metabolism; D006868:Hydrolysis; D007700:Kinetics; D013294:Lactococcus lactis / Q000201:enzymology*; D008969:Molecular Sequence Data; D010455:Peptides / Q000378:metabolism
D004723:Endorphins; D010455:Peptides; C021968:beta-casomorphins; D004152:Dipeptidyl-Peptidases and Tripeptidyl-Peptidases; D018819:Dipeptidyl Peptidase 4