Artificial and natural thermostabilization of subunit enzymes. Do they have similar mechanism?

Rabbit skeletal muscle glyceraldehyde-3-phosphate dehydrogenase was stabilized by intramolecular intersubunit crosslinking with diimidoesters. Half-inactivation temperature for optimal cross-linker-treated enzyme preparation increased by 11 degrees C. Stabilization effect correlated with the content of crosslinked fractions in enzyme preparation, as proved by SDS gel-electrophoresis. It is proposed that artificial crosslinks stabilize the enzyme in a similar fashion to salt bridges in the thermophilic bacteria enzymes, i.e. preventing dissociation into inactive subunits.