TABLE 1

Catalase enzyme activities in whole cells and in different subcellular fractions of insulin-producing RINm5F cells, preferentially overexpressing catalase in cytoplasm (cyto) or mitochondria (mito 1 and 2)

Cell fractionsControlCytoMito 1Mito 2
Total12 ± 2 (8)178 ± 21 (11)172 ± 24 (8)269 ± 30 (11)
Mitochondrial fraction9 ± 1 (7)155 ± 33 (10)192 ± 43 (7)300 ± 36 (10)
Microsomal fraction3 ± 1 (7)7 ± 1 (10)6 ± 1 (7)7 ± 1 (10)
Cytoplasmic fraction11 ± 2 (7)204 ± 37 (10)129 ± 17 (7)142 ± 15 (10)
Ratio mito/cytosol1.0 ± 0.3 (7)0.8 ± 0.1 (10)1.8 ± 0.5 (7)*2.5 ± 0.5 (10)
  • Data are means ± SE (no. experiments). Catalase enzyme activities were determined in whole cells (total activity) and in mitochondrial, microsomal, and cytoplasmic fractions of insulin-producing RINm5F cells overexpressing catalase preferentially in the cytoplasm (cyto) or mitochondria (mito 1 and 2). In addition, the ratio between the enzyme activity in the mitochondrial and in the cytoplasmic fraction is given.

  • *

    * P < 0.05;

  • P < 0.01 vs. the cyto clone and the control clone (Student’s t test).