Spodoptera frugiperda Sf-9 (Sf-9) and Trichoplusia ni BTI-Tn-5BI-4 (Tn-5BI-
4) insect cell lines were found to contain unique assemblages of antioxidan
t enzymes. Specifically, the Sf-9 insect cell line contained Manganese and
Copper-Zinc superoxide dismutase (MnSOD and CuZnSOD) for reducing the super
oxide radical (O-2(.-)) to hydrogen peroxide (H2O2) and ascorbate peroxidas
e (APOX) for reducing the resulting H2O2 to H2O. Approximately one third of
the total SOD activity was found to be MnSOD. The Tn-5BI-4 cells were also
found to contain MnSOD (similar to two thirds of the total SOD activity),
CuZnSOD and APOX activities. However, the Tn-5B1-4 cell line, in contrast t
o the Sf-9 cell line, contained catalase (CAT) activity for reducing H2O2 t
o H2O. Both the Sf-9 and Tn-SB1-4 cell lines contained glutathione reductas
e and dehydroascorbic acid reductase activities for regenerating the reduce
d forms of glutathione and ascorbic acid, respectively. In addition, both c
ell lines contained glutathione S-transferase peroxidase activity towards h
ydroperoxides other than H2O2. Finally, neither cell line contains the glut
athione peroxidase activity that is ubiquitous in mammalian cells. (C) 2001
Elsevier Science Inc.