ENZYMIC AND IMMUNOCHEMICAL PROPERTIES OF LYSOZYME .2. CONFORMATION, IMMUNOCHEMISTRY AND ENZYMIC ACTIVITY OF A DERIVATIVE MODIFIED AT TRYPTOPHAN

The six tryptophan residues in lysozyme were modified by reaction for 3 min with 2-nitrophenyl sulfenyl chloride in 98 per cent formic acid. The modified enzyme showed a sedimentation coefficient (S020, w) of 4.05S compared to 1·91S for native enzyme and 1·95S for formic acid-treated lysozyme. Significant conformational changes accompanied the modification as evaluated by the availability of the disulfide linkages to reduction and the susceptibility of the modified protein to proteolysis. Loss of enzymic activity as well as a marked decrease in the ability of modified lysozyme to react with antilysozyme antibodies were observed. There was evidence that modified lysozyme showed decreased antigenicity in rabbits. © 1969.