Table 3.

Comparison of Ca²⁺-Dependent TGase Activity with KGDHC, GDH, and mitAspAT Activities in Mitoplasts (P7) Derived from Nonsynaptosomal Mouse Brain Mitochondria^a

enzyme	specific activityb	recovery in P7 relative to homogenate (H) %
KGDHC	108, 129	4.0, 8.8
GDH	97, 52	3.5, 4.9
mitAspAT	657, 453	5.0, 4.3
TGase	4.3 ± 1.5c (6.4, 1.5, 5.0)	0.14 ± 0.04

^aThe data were obtained from two of the mouse brain preparations described in Table 2. In the case of TGase, activity was measured in an additional preparation so that the values shown for this enzyme are for n = 3. The actual values are shown in parentheses. The protein concentrations in the nonsynaptosomal mitochondrial fraction (P6; Table 2) and the mitoplast fraction (P7) were 48 and 58.4, and 20 and 37.8 mg/mL, respectively.

^bUnits are nmol min⁻¹ (mg of protein)⁻¹, except TGase, where specific activity is expressed as pmol h⁻¹ (mg of protein)⁻¹.

^cDifferent from zero with p < 0.05 by the one-tailed t test; p < 0.001 by the χ² test; 95% confidence interval from −2.0 to 10.6.