Figure 4
From: Dipeptidyl peptidase IV, aminopeptidase N and DPIV/APN-like proteases in cerebral ischemia
DPIV and DPIV-like protease activities after transient cerebral ischemia. (A) Relative Vmax of DPIV/DPIV-like activity in adult rat cortices of ipsilateral (infarct, black bars) or contralateral (control, gray bars) hemispheres at different time points after eMCAO. A pronounced Vmax increase in the ipsilateral cortex compared to the contralateral cortex was detectable 7 day post insult (+165%, for details, see text). At earlier time points, differences between both hemispheres were not found (n = 5). (B) Michaelis-Menten kinetics of total DPIV/DPIV-like activity in infarct (solid line) and control cortices (dashed line) 7 days post eMCAO. Ipsilateral and contralateral cortices revealed similar Km values, i.e. ipsilateral: Km = 380 ± 40μM; n = 5; contralateral: Km = 330 ± 20μM; n = 5, whereas Vmax differed significantly (p = 0.025, t-test), i.e. ipsilateral: 6.9 ± 1.5 nmol/min/mg protein, n = 5; contralateral: 2.6 ± 0.4 nmol/min/mg protein, n = 5. (C) Relative fractional contribution of DPII, DP8/9 and DPIV activity to total DPIV-like protease activity (Gly-Pro-pNA cleavage) in the ipsilateral (infarct, left bar group) and contralateral (control, right bar group) cortex at different time points after eMCAO (pH 7.5). (D) Vmax of DPII, DPIV and DP8/9 in the ipsilateral and contralateral cortex. (E) Relative activities of DPII, DPIV or DP8/9 in ipsilateral (black bars) or contralateral control (gray bars) cortices 7 days post eMCAO. Data are means ± SD from 5 independent experiments. *p = 0.0001; **p = 0.0004 (t-test).