Vs. Haritos et al., CYTOCHROME-P450 MONOOXYGENASE AND GLUTATHIONE-S-TRANSFERASE ACTIVITY OF 2 AUSTRALIAN TERMITES - MASTOTERMES DARWINIENSIS AND COPTOTERMES ACINACIFORMIS, Insect biochemistry and molecular biology, 24(9), 1994, pp. 929-935
The major detoxication enzymes have been characterized in preparations
of two economically important termite species. Mastotermes darwiniens
is microsomes contained a similar quantity of total cytochrome P450 as
Coptotermes acinaciformis but the activities of aldrin epoxidase (AE)
, 7-ethoxyresorufin O-deethylase (EROD) and 7-ethoxycoumarin O-deethyl
ase (ECOD) were 4.5, 5.8 and 17 times higher, respectively. Compared w
ith other insects, AE activity in these two termite species is low, ER
OD activity moderate and ECOD activities are high, especially in M. da
rwiniensis. The cytosolic GST activity of C. acinaciformis toward chlo
ro-3,5-dinitrobenzene (CDNB) was 3.13 mu mol min(-1) mg(-1), > 3 fold
higher activity than M. darwiniensis cytosol. Apparent K-m values of 1
.87 mM for CDNB and 0.84 mM for glutathione were determined in C. acin
aciformis cytosol. 7,8-Benzoflavone dramatically reduced EROD activity
in microsomes of both termite species but had significantly lower inh
ibitory effect on ECOD activity. The addition of SKF 525A to termite m
icrosomes inhibited both EROD and ECOD activities. Multiple isoenzymes
of cytochrome P450 in termites are indicated by these findings. The d
istinctly different substrate specificities and lambda(max) of the CO
difference spectra from M. darwiniensis and C. acinaciformis microsome
s may arise from differences in the cytochrome P450 isoenzymes between
the two species.