Programme

The research in the Antarctic this season represents the third phase in a three phase programme to study the detoxication systems of antarctic fish. The first two phases involve the thermodynamic characterization of a reaction with the general substrate 1-chloro-2, 4-dinitrobenzene.

The first phase involves the thermodynamic characterization of the spontaneous reaction, so reaction velocity con be calculated at any given pH or temperature. This allows extrapolation to the physiological conditions of antarctic fish. Results show that the spontaneous reaction will proceed 30 times slower under antarctic conditions.

Relevant thermodynamic parameters calculated for the reaction are activation enthalpy 49 KJ mol⁻¹ and enthalpy of glutathione sulphydryl proton 31.6 KJ mol⁻¹.

The second phase involves the thermodynamic characterization of enzymes from Dissostichus mawsoni being compared with those of other organisms with different temperature regimes. Results gained to date give activation energies for the catalysed reaction between 1-chloro-2, 4-dinitrobenzene of 56.8±7.8 KJ mol⁻¹ for D.mawsoni, 47.0±3.8 KJ mol⁻¹ for the moth Galleria mellonella and 34.8±2.6 KJ mol⁻¹ for rat glutathione-s-transferase 1,2.

The third phase involves the characterization of enzyme levels with different substrates. In particular endogenous xenobiotic substrates will be examined. These include the lipid peroxide cumene hydroperoxide, a substrate used in the Antarctic this season.

To summarize, the first phase examines the need for a detoxication system. The second examines any structural evolutionary change unique to the Antarctic and the third examines specialization of enzyme type that may have occurred to facilitate life in the antarctic waters.