Regeneration to the Native Form of Hen Egg-White Lysozyme from Its Protected Derivatives

The following derivatives of hen egg-white lysozyme were prepared from native hen egg-white lysozyme, 2-chlorobenzyloxycarbonyl-lysozyme, S-(4-methylbenzyl)-reduced-lysozyme, and 2-chlorobenzyloxycarbonyl-S-(4-methylbenzyl)-reduced-lysozyme. Treatment of these derivatives with anhydrous liquid hydrogen fluoride for 90 min at 0 °C yielded fully active lysozyme with recoveries, in order, of 23, 12, and 7.4%. The properties of the lysozyme recovered were identical with those of native hen egg-white lysozyme, and crystals of this material were indistinguishable from those of native enzyme.